Chapter 23: Periprosthetic Fractures

William M. Ricci

Chapter Outline

Introduction to Periprosthetic Fractures

Periprosthetic fractures continue to increase in frequency. This is due, in part, to the increasing number of primary and revision arthroplasties performed annually and also to the increasing age and fragility of patients with such implants. All types of periprosthetic fractures can present unique and substantial treatment challenges. In each situation, the presence of an arthroplasty component either obviates the use of, or increases the difficulty of, standard fixation techniques. In addition, these fractures often occur in elderly patients with osteoporotic bone making stable fixation with traditional techniques even more problematic. 
The difficulty in management of periprosthetic fractures regardless of location is evidenced by the array of treatment options described in the literature without a clear consensus emerging on the most appropriate method.140,160,228,229,230 Treatment of the most common periprosthetic fractures, those of the femoral shaft and those of the femoral supracondylar region, has focused on open reduction and internal fixation (ORIF) or revision arthroplasty procedures with or without supplementary autologous or allogeneic bone grafting.39,99,222 Most recently, treatment strategies to accelerate weight bearing have suggested benefits with regard to mortality.149,151,210 Successful application of these strategies can be extrapolated to periprosthetic fractures in other anatomic locations but must also consider the fracture location relative to the arthroplasty component, the implant stability, the quality of the surrounding bone, and the patient’s medical and functional status.64 

Assessment of Periprosthetic Fractures

Injury Mechanisms for Periprosthetic Fracture

Low-energy falls account for the mechanism of injury in most patients with periprosthetic fractures of both the upper and lower extremity.81,147,165,229 Lower extremity fractures tend to occur postoperatively rather than intraoperatively whereas a relatively larger proportion of upper extremity periprosthetic fractures, especially those about humeral shoulder arthroplasty stems, occur intraoperatively. Postoperative low-energy falls account for greater than 75% of all periprosthetic femur fractures from the Swedish registry database,165 whereas a majority, up to 76% of humeral fractures, have been reported to occur intraoperatively.32,261 Periprosthetic fractures are noted to be more common after revision arthroplasty than after primary arthroplasty. This is likely because of the reduced bone stock often present after revision.165 High-energy trauma accounts for only a small percentage of periprosthetic fractures and these are usually associated with a more comminuted fracture pattern than seen with low-energy fractures.13 Intraoperative fractures of both the upper and lower extremities occur more commonly during revision procedures and with implantation of large noncemented stems.188,236 The risk increases when there is mismatch between the shape of long prosthetic stems and the shape of the bone.305 Specific to periprosthetic fractures about a total knee arthroplasty (TKA), another mechanism is related to forced manipulation of a stiff knee. 

Injuries Associated with Periprosthetic Fractures

Given the predominance of low-energy injury mechanisms associated with periprosthetic fractures, associated injuries are relatively uncommon. Of course, vigilance is required to avoid missing the occasional associated injury. On the occasion when high-energy mechanism is the cause of a periprosthetic fracture, that patient should be evaluated just as any other patient with a high-energy injury mechanism. 

Signs and Symptoms of Periprosthetic Fractures

When evaluating patients with obvious or even suspected periprosthetic fractures, the history should include a detailed account of the status of the arthroplasty including as much detail as possible on the date of implantation, the specific prosthesis used, the index diagnosis for implantation, and the relevant history related to the associated arthroplasty. Additional secondary procedures should be carefully cataloged as well as other complications such as prior infection. Occult infection may be associated with and potentially contributing to periprosthetic fracture.42 Laboratory markers such as ESR and C-reactive protein, in the setting of fracture, are likely to be elevated regardless of infection status and are therefore of limited value for the diagnosis of infection in this setting.42 
The baseline functional status specific to the involved joint as well as to the patient as a whole, such as handedness, occupation, ambulatory status, and any need for assist devices, are a standard part of the history. The time course of any recent change in status or symptoms related to the arthroplasty can heighten suspicion of a subtle periprosthetic fracture or prefracture implant loosening. A history of mechanical symptoms such as start-up pain, increasing difficulty with ambulation, progressive limb shortening, and deformity of the extremity are all associated with prosthetic loosening prior to the fracture and will impact the treatment. 
The standard comprehensive orthopedic examination is warranted with specific attention to prior surgical wounds about the joint in question, the presence or absence of associated lesions such as venous stasis or diabetic ulcers of the ipsilateral or contralateral limbs, limb length evaluation, as well as strength and neurologic evaluation. Status of the abductors for the hip and the extensor mechanism for the knee are essential parts of the evaluation. Obviously, in cases of displaced fracture, many of these parameters will be abnormal and not represent the patient’s baseline status. However, it is still important to obtain a comprehensive history, as clues to potential etiologic factors to the acute fracture such as implant loosening, osteolysis, and infection may need to be addressed during the course of fracture repair. 
Direct observation of periprosthetic fractures occurs when the fracture happens intraoperatively. A pitch change during insertion of the trial or final prosthesis alerts the surgeon to the possibility of fracture and should prompt an appropriate investigation starting with direct observation. Similarly, an abrupt easing of insertion resistance can be a subtle sign of fracture or perforation. 

Imaging and Other Diagnostic Studies for Periprosthetic Fractures

The diagnosis of a postoperative periprosthetic fracture is usually obvious. The patient typically has an abrupt onset of pain and deformity associated with trauma. However, more subtle fractures can occur especially when associated with significant osteopenia or osteolysis. In cases of fracture related to severe osteolysis, the trauma is usually trivial or absent. The extent of bone loss is usually significant and makes treatment more difficult. Although challenging, it is important to recognize these cases. Clinical suspicion is necessary to instigate a specific radiographic evaluation to rule out fracture. 
The standard radiographic evaluation of periprosthetic fractures should include plain AP and lateral views to include the joint in question and full length radiographs of the bones above and below the joint. Attention should be paid not only to fracture specifics but also to an evaluation of the prosthesis relative to the fracture as well as the prosthesis relative to the native bone to which it is secured. It is useful to assess for prosthetic loosening, presence of bone loss and osteolysis, and prosthetic and limb alignment. Prefracture radiographs, when available, can provide insight to the time course of any existing or impending prosthetic failure, specifically osteolysis, progression of cortical erosions, and presence of any cortical penetrations or notching. In addition, in more subtle cases, prefracture radiographs can help to identify subtle changes in implant position which may be the only clue to a loose implant associated with a fracture. Radiographic features of a loose stem include progressive change in stem position (e.g., subsidence), global radiolucency around the stem, distal pedestal formation, and cement mantle fracture (for cemented stems). Despite radiographic appearance of implant stability, components may be loose based on intraoperative findings.49 Therefore, surgical planning should account for this contingency. 
Identifying a well-fixed stem is also important. Radiographic features of this include bony “spot welding” to the implant, proximal stress shielding or remodeling above a distally well-fixed stem, and distal bone condensation or remodeling around a proximally fixed stem. 
Diagnosis of intraoperative fracture can be from direct observation or indirectly based on suspicion from auditory changes in the pitch of sounds coming from mallet blows of a broach or implant. In such circumstances, intraoperative radiographs should be obtained to define the extent of the fracture which can be more extensive than seen under direct vision. Immediate postoperative radiographs are done in many institutions and should be checked meticulously to ensure the imaged area is adequate to diagnose subtle fractures. 
Cross-sectional imaging is not routinely required to evaluate periprosthetic fractures. However, significant advances have been made to reduce metal artifact of both CT scans and MRI scans which may help in evaluating subtle fractures or in the evaluation of available bone stock for fracture repair.199,204,290 

Outcome Goals and Outcome Measures for Periprosthetic Fractures

In the most general sense, the goals of periprosthetic fracture care are no different than the goals of treatment of any other periarticular fracture. These goals include timely and uncomplicated fracture union, restoration of alignment, and return to preinjury level of pain and function. By definition, periprosthetic fractures are not associated with normal joints. Therefore, neither baseline painless normal joint function and normal anatomic alignment cannot be assumed nor can return to normal function be the de facto goal. Instead, an accurate history of prefracture function should be elicited to help guide goals and prognosis. In the setting of a poorly functioning loose prosthesis, return to a better functional level after fracture fixation and revision arthroplasty may be a reasonable goal. If prefracture malalignment existed, a careful determination must be made whether restoring baseline alignment or normal alignment should be the goal. This decision is often predicated on the alignment of the prosthesis relative to the bone on the nonfractured side of the joint which may provide an inherent compensatory alignment. A unique consideration when treating periprosthetic, rather than native, periarticular fractures is consideration of prosthesis stability and the potential need for future revision arthroplasty. The additional goal therefore is to assure stability of the prosthesis and restoration of adequate bone stock to maximize the potential success of any subsequent procedures. 

Periprosthetic Acetabular Fractures

Incidence, Risk Factors, and Prevention of Periprosthetic Acetabular Fractures

Periprosthetic acetabular fractures are very uncommon. They may occur intraoperatively or postoperatively. Intraoperative fractures are most commonly associated with insertion of noncemented components.101,252 Identification of intraoperative fractures can be difficult. It has been suggested that published results of intraoperative fractures that use only AP radiographs for diagnosis may underestimate the true incidence as oblique views were found to be required to accurately identify the presence of an occult fracture.135 
The incidence of intraoperative fracture was found to be 0.3% in a series of 7,121 primary total hip arthroplasties (THAs) performed at the Mayo Clinic between 1990 and 2000.101 All 21 fractures occurred during insertion of a noncemented component resulting in a fracture incidence of 0.4% for noncemented components and 0% for cemented components. The fracture occurrence was most common during impaction of the final component (16/21) but fracture was also noted to occur during reaming (3/21) and during initial dislocation (2/21). This study also demonstrated that elliptical designs had a significantly higher rate of fracture (0.7%) compared to hemispherical designs (0.09%). This increased risk of fracture with elliptical designs was largely related to the association with a monoblock design, one with the liner bound to the shell such that visualization of implant seating through screw holes is not possible. Monoblock elliptical components had a 3.5% incidence of fracture whereas modular elliptical components had a 0.3% incidence. There was no statistical difference in fracture between the modular elliptical and hemispherical designs supporting the theory that the reduced feedback from the monoblock design may be a greater contributing factor than the elliptical shape. The size of the component relative to the reamed acetabulum also affects risk of fracture. In a cadaveric study, there were more fractures with components oversized by 4 mm than with components oversized by 2 mm.135 This study also showed that more force was required to seat the 4-mm oversized components (3,000 N) than the 2-mm oversized components (2,000 N). 
Postoperative periprosthetic acetabular fractures have an exceedingly low rate of occurrence. In another largely cohort study from the Mayo Clinic (23,850 patients), the incidence of postoperative acetabular fracture was 0.07%.216 A number of factors have been implicated to be associated with periprosthetic acetabular fracture. Although low-energy trauma, most notably falls from a standing height, is the most common mechanism,216 fractures may also be seen without antecedent trauma or on occasion from high-energy trauma.89,107 In some occult cases, especially those diagnosed soon after arthroplasty, a missed intraoperative fracture may be causative. De novo fractures in the postoperative period that are not associated with trauma are normally associated with reduced bone quality or quantity or both. Osteolytic lesions clearly reduce bone stock and not surprisingly fractures through such lesions have been reported.243 An apparent acetabular fracture years removed from surgery with minimal trauma is likely related to progressive particle disease. Based on indirect evidence, usually in the form of a disproportionately high ratio of females, many authors have implicated osteoporosis as a risk factor.101,252,260 Weakening of the pelvic bone stock associated with reaming required to obtain a secure fit of a large-diameter hemispherical component for revision resulted in a 1.2% incidence of transverse acetabular fracture without associated trauma.260 Stress fracture has also been reported in association with primary cemented and revision arthroplasty and should be considered with acute pain onset especially when associated with abrupt increased activity level.8,189 Infection may be an etiologic factor predisposing to stress fracture189 and therefore concomitant infection should be considered anytime a stress fracture is identified. The prudent clinician should also consider periprosthetic acetabular fracture whenever there is acute onset of pain associated with total hip arthroplasty especially in situations with compromised bone stock. 
Avoidance of fracture may be the first step. To this end, the degree of reaming is of paramount importance. Too much reaming, especially in the revision setting where bone stock is already compromised or in the presence of serve osteoporosis, should be avoided. Careful reaming without violation of the acetabular walls including the medial wall will reduce risk for fracture and also provide the necessary foundation for component stability.58 The degree of reaming relative to the size of an uncemented implant is also critical. Under reaming of the acetabulum more than 2 mm is ill advised as the more oversized the component is, the higher is the risk of fracture.135 Trialing is helpful to identify areas of impingement and the aggressiveness of the bony press fit. Care must also be exercised during insertion of the component. Excessive force should be avoided and failure of the component to seat properly with successive mallet blows should be an indication for increased caution and possibly additional reaming. 

Classification of Periprosthetic Acetabular Fractures

Peterson and Lewallen distinguished two types of periprosthetic acetabular fractures based on the stability of the acetabular component.216 Type I fractures are associated with a radiographically stable component, one where there was no change in the position of the component compared with that seen on radiographs made before the fracture (if available) and where gentle passive range of motion (ROM) of the hip caused little or no pain. Fractures were considered type II if the acetabular component was obviously displaced or radiographically loose and there was notable pain with any motion of the hip. This classification scheme neither does account for the morphology of the fracture nor does it include the relative location of the fracture. A modification of the acetabular fracture classification system of Letournel (see Chapter 47 Acetabulum Fractures) that includes a category for fractures of the medial wall of the acetabulum, a location that is common when these fractures occur postoperatively, provides more insight into the fracture pattern and location. In Peterson’s series of postoperative periprosthetic acetabular fractures occurring at an average of 6.2 years after the index arthroplasty procedure, there were eight type I fractures and three type II fractures.216 Medial wall fracture was the most common pattern (5 of the 11 cases) followed by posterior column in three, transverse in two, and anterior column in one patient. Given the need to consider both the stability of the component and the fracture location and pattern to determine a treatment plan, it seems that neither classification system is sufficient without consideration of the other. 

Management Principles for Periprosthetic Acetabular Fractures

Treatment of periprosthetic acetabular fractures requires consideration of many factors. In addition to the obvious consideration of patient factors such as medical condition and functional demands, the timing of the fracture (intraoperative or postoperative), the displacement, the location, and the stability of the component should be accounted for in the decision algorithm, the overall goals being union of the fracture and return of the patient to their prefracture functional level with a stable acetabular component. 
Nonoperative treatment of a periprosthetic acetabular fracture is not usually indicated when associated with a loose or unstable component. For early fractures, those identified on radiographs shortly after surgery, nonoperative treatment may be an option assuming that the component had good stability intraoperatively and did not migrate on serial x-rays, and that there is no pelvic discontinuity or major interruption of the columns. For late fractures associated with osteolysis (and usually with trivial trauma) there are only rare indications for nonoperative treatment. For those late fractures associated with a significant high speed mechanism in a well-functioning hip without osteolysis, nonoperative treatment has a role if the pelvic fracture does not destabilize the socket or predispose to migration (similar criteria as in the immediate postoperative period). 
Operative management of periprosthetic acetabular fractures can take many forms. The strategy is determined by a number of factors: the timing of the diagnosis (intraoperative or postoperative), the stability of the acetabular component, the fracture location, and the fracture displacement. Fixation of minimally displaced fractures identified intraoperatively can be achieved with screws through a multihole acetabular component. More widely displaced fractures may require formal ORIF with plate fixation with revision of the acetabular component.89 Percutaneous screw fixation utilizing computer navigation has also been reported.94 

Management Principles for Intraoperative Periprosthetic Acetabular Fractures

Treatment of intraoperative acetabular fractures begins with the evaluation of the acetabular component stability and definition of the fracture location and displacement. Any change in pitch upon implantation of the component or sudden loosening of a component should alert the surgeon to the possible presence of a periprosthetic fracture. The acetabular shell should be removed and the pelvis visually inspected systematically with particular attention to the posterior column, dome, and anterior column. Intraoperative radiographs may help define the location and degree of displacement. Anterior–posterior radiographs alone may not be sufficient to identify such fractures, therefore obturator and iliac oblique views should also be included.135 Small fractures of either the anterior, medial, or posterior walls may not affect the stability of the implant and can be treated without any further surgery. If the component is relegated unstable by a large wall fracture or a fracture that traverses one of the acetabular columns, then additional steps are required to insure component stability that may involve adjunctive fracture fixation. When the fracture is nondisplaced, screw fixation through holes in the acetabular component may be sufficient to provide component stability. However, if a column is involved there should be a low threshold for independent reduction and plate and screw fixation of the acetabular fracture, especially if it is displaced. Bone grafting of the fracture site with reamings or morselized femoral head may be beneficial to speed fracture healing.252 After plate and screw fixation of the acetabulum, the acetabulum should be reamed line-to-line for a new multihole component which is carefully impacted and then stabilized with multiple screws. When possible, screws on either side of the fracture are preferred. Weight bearing is typically restricted for at least 6 weeks based on radiographic and clinical evidence of fracture healing unless the fracture is of the acetabular wall and is very small. 

Management Principles for Postoperative Periprosthetic Acetabular Fractures

Postoperative periprosthetic acetabular fractures are very different than those occurring intraoperatively. Intraoperative fractures are usually minimally displaced, most commonly involve the acetabular walls rather than columns, generally require minimally additional surgical management, and are generally associated with good results. Postoperative fractures, on the other hand, are usually more complex, require a greater degree of surgical intervention, and in general have poorer results. Before treatment can be instituted, etiologic factors should be considered, the stability of the cup determined, and the available bone stock quantified. 
Fractures about stable components (type I fractures) with good bone stock can be expected to have a high union rate with nonoperative management consisting of protected weight bearing for 6 to 12 weeks. Despite union and in distinction from similar intraoperative fractures, the fate of the component is dubious. These components have a high likelihood of loosening and therefore have results inferior to those seen for type I fractures occurring intraoperatively. Immediate surgical treatment for fractures with stable components in the absence of osteolysis may be indicated for widely displaced fractures. Component revision should be considered to accompany reduction and fixation of the fracture in such instances; however, there is little in the way of published results to guide this decision making. 
Fractures that are associated with a loose acetabular component, type II fractures, generally require revision of the acetabular component and supplemental fracture fixation with plates and screws. The type of component revision is highly dependent upon the available bone stock. CT scan is useful to identify the type of reconstruction option needed. If there is an intact posterior column and dome, bone grafting and use of a hemispherical revision socket with screws is feasible though backup options should always be available. In cases with severe osteolysis or pelvic discontinuity, reconstruction typically requires bone grafting, augments, a reconstruction cage, or some combination of these methods. After removal of the acetabular component, the fracture is fixed with plates and screws based on the fracture pattern to restore, to the extent possible, the integrity of the acetabular columns. Bone grafts, either morselized or structural depending upon the size and location of the defect, are used to re-establish any residual structural deficiencies. A large multihole cup with screws or a cage is used to complete the reconstruction. There is little published data to guide subtle variations in treatment or to establish prognosis. 
Periprosthetic acetabular fractures in association with osteolysis have been the subject of case reports.40,243 Regardless of the healing potential of the fracture, which in most cases is nondisplaced, surgical management is indicated for the underlying osteolytic process as well to deal with the loose component that in most instances accompanies these fractures. Treatment is primarily directed to management of the osteolytic lesions with bone graft. Revision of the acetabular component is usually required even if stable so that adequate access to the lesions for bone grafting can be accomplished. 

Preoperative Planning for Management of Periprosthetic Acetabular Fractures

Component revision, ORIF, and bone grafting should be prepared for, even if one or more of these options is considered unlikely based on preoperative assessment (Table 23-1). Intraoperative findings can be different than expected based on preoperative evaluations. An array of acetabular components may be required, including multiholed cups, jumbo sizes, as well as cages. ORIF of periprosthetic acetabular fractures requires standard 3.5-mm pelvic reconstruction plates and 3.5-mm cortical screws. 4.5-mm cortical screws may also be required, either to serve as anchor points for reduction clamps or as a lag screw across a column fracture. Specialized clamps (see Chapter 47 Acetabular Fractures) are often required for the reduction maneuvers. Allograft, usually in the form of morselized femoral head or cancellous croutons or chips, is typically used for osteolytic lesions. 
 
Table 23-1
Surgical Treatment of Periprosthetic Acetabular Fractures
Preoperative Planning Checklist
  •  
    OR table: Radiolucent table that allows imaging of hip and pelvis
  •  
    Position: Lateral
  •  
    Fluoroscopy location: From front of patient (opposite from operating surgeon)
  •  
    Equipment:
    •  
      Reduction clamps specific to ORIF of acetabular fractures
    •  
      Retractors specific to ORIF of acetabular fractures
    •  
      Bone mill or other method to morselize allograft
  •  
    Implants:
    •  
      3.5-mm pelvic reconstruction plates and associated screws
    •  
      Array of acetabular components including:
    •  
      Cups with multiholes
    •  
      Jumbo-sized cups
    •  
      Acetabular cages
    •  
      Allograft
X

Positioning and Surgical Approach for Management of Periprosthetic Acetabular Fractures

The patient is generally positioned laterally on a radiolucent operating table with a beanbag used for support. Peg boards and other positioners often used for positioning during hip arthroplasty are typically not radiolucent, so they should be avoided when fracture fixation will require fluoroscopy. Although other approaches can be successfully utilized for hip arthroplasty, simultaneous fixation of the acetabular fracture and management of the acetabular component generally necessitate the posterior Kocher–Langenbeck approach. The C-arm for intraoperative fluoroscopic imaging is placed from the front of the patient, on the side opposite to the operating surgeon. The knee should remain flexed throughout the procedure to reduce tension and risk of injury to the sciatic nerve.22 

Surgical Technique for Management of Periprosthetic Acetabular Fractures

Details for the surgical technique for ORIF of acetabular fractures as presented in Chapter 47 Acetabular Fractures generally apply to ORIF of periprosthetic acetabular fractures. The differences come with regard to management of the acetabular cup and any associated osteolytic lesions. When the cup is stable, steps for ORIF of the periprosthetic acetabular fracture (Table 23-2) are little different from ORIF of a native fracture. Exposure is followed by identification and debridement of the primary fracture lines. Cup stability should be confirmed and osteolytic lesions bone grafted through the fracture if easily accessible. Care must be taken not to overpack the lesion so as to prevent fracture reduction. An alternative to filling osteolytic lesions through the fracture is to fill them through separate cortical windows which can be done after reduction of the fracture. A basic tenet of acetabular fracture surgery is anatomic reduction of the articular surface. In the presence of an acetabular cup, such precision is not required, but anatomic reduction should still be strived for to maximize healing potential. Fixation of reduced fractures is with standard pelvic reconstruction plates and screws. 
Table 23-2
Surgical Treatment of Periprosthetic Acetabular Fractures with a Stable Cup
Surgical Steps
  •  
    Expose the acetabulum including the posterior wall and column
    •  
      Protect sciatic nerve with retractors, hip extension, and knee flexion
  •  
    Identify and debride fracture lines and fragments
  •  
    Confirm cup stability
  •  
    Fill osteolytic lesions through fracture or via separate window
    •  
      Be careful to avoid blocking fracture reduction
    •  
      If window is used, this step can come after reduction and fixation
  •  
    Apply reduction maneuvers and clamp fracture
  •  
    Insert a lag screw, if possible, across the fracture for provisional fixation
  •  
    Definitively stabilize fracture with a contoured 3.5-mm reconstruction plate
  •  
    Standard closure
X
When the acetabular component is loose, surgical treatment includes component revision (Table 23-3). The loose component can be removed either before or after provisional fracture reduction. Sometimes the presence of the loose cup can provide a template for fracture reduction. More often, the component is removed after exposure and prior to fracture reduction. The femoral head is dislocated from the component and retracted anteriorly to allow unencumbered exposure to the acetabulum. This can require wide exposure and extensive release of the soft tissues about both the acetabulum as well as the proximal femur. Fracture reduction and fixation as described previously is followed by grafting of any bone defects and implantation of a new acetabular component. When massive bone loss is present, reconstruction with an acetabular cage is indicated. 
Table 23-3
Surgical Treatment of Periprosthetic Acetabular Fractures with an Unstable Cup
Surgical Steps
  •  
    Expose the acetabulum including the posterior wall and column
  •  
    Protect sciatic nerve with retractors, hip extension, and knee flexion
  •  
    Perform hip arthrotomy
  •  
    Identify and debride fracture lines and fragments
  •  
    Dislocate femoral head and retract it anteriorly to expose acetabular component
  •  
    Remove loose cup
  •  
    Apply reduction maneuvers and clamp fracture
  •  
    Insert a lag screw, if possible, across the fracture for provisional fixation
  •  
    Definitively stabilize fracture with a contoured 3.5-mm reconstruction plate
  •  
    Fill osteolytic lesions and bone defects through exposed acetabular surface
  •  
    Implant new acetabular component
  •  
    Reduce hip
  •  
    Reconstruct posterior pseudocapsule
  •  
    Standard wound closure
X

Potential Pitfalls and Preventative Measures for Management of Periprosthetic Acetabular Fractures

It is often difficult to determine the status of the acetabular cup stability after periprosthetic acetabular fracture (Table 23-4). A careful history of signs of cup loosening prior to fracture as well as careful scrutinization of prefracture radiographs, if available, and postfracture radiographs with particular attention to cup stability should be performed on a routine basis. Even when preoperative evaluation points to a stable cup, careful intraoperative evaluation of component stability should be performed. Because unexpected cup instability can occur, the surgeon should be prepared for cup revision in all operative cases for periprosthetic acetabular fracture. 
 
Table 23-4
Surgical Treatment of Periprosthetic Acetabular Fractures
Potential Pitfalls and Preventions
Pitfalls Preventions
1. Cup instability Obtain accurate history of potential symptoms of prefracture implant instability
Careful evaluation of prefracture and postfracture imaging
Careful intraoperative assessment of cup stability even when history and radiographs indicate cup stability
2. Fracture malreduction and/or nonunion Careful preoperative evaluation of fracture morphology with Judet radiographs and CT scanning
Comprehensive plan for reduction and fixation based on principles of acetabular fracture management
Avoid temptation to accept imperfect reduction because of lack of need for reduction of articular surface
3. Missed intraoperative fracture Low threshold for intraoperative radiographs with any suspicion for intraoperative fracture
X
Because there is no articular surface remaining, it is tempting to settle for an imperfect fracture reduction. Poor reduction with remaining fracture gaps can lead to nonunion and therefore efforts should be made to obtain an anatomic reduction. To obtain a satisfactory reduction, careful preoperative evaluation of the fracture morphology and a comprehensive plan for reduction and fixation, just as is performed for native acetabular fractures, should be performed. Occasionally, an intraoperative acetabular fracture is identified postoperatively. Although usually these are minimally displaced and can be treated nonoperatively with good results, occasionally these fractures require revision surgery. To avoid missing intraoperative fractures, a low threshold for intraoperative imaging should coincide with any suspicion for intraoperative fracture. 

Outcomes for Periprosthetic Acetabular Fractures

Sharkey et al.252 identified nine intraoperative fractures. Two were small posterior wall fractures that did not compromise component stability and therefore had no additional treatment and were allowed immediate weight bearing. One similar fracture had no additional intraoperative treatment but had restricted postoperative weight bearing. The other six were managed with screws either through the component or placed peripherally outside the cup and in four of these autograft was packed into the fracture site. Other than one patient who required resection arthroplasty because of infection, all fractures healed and no patient required revision at an average follow-up of 42 months. Haidukewych et al.101 identified 21 intraoperative fractures occurring during primary arthroplasty. Seventeen were judged not to compromise component stability and received no additional intraoperative treatment. In 4 of their 21 patients, the component was found to be unstable necessitating a change in component to one that provided supplemental screw fixation. No adjunctive plates or screws outside the component were used. All patients were treated with protected weight bearing. All fractures healed and no patient required revision for loosening at an average follow-up of 44 months. 
In the series of Peterson and Lewallen,216 75% of patients treated nonoperatively for a type I fracture (stable component) eventually required revision of their acetabular component. Of the eight fractures, six healed but four eventually required revision of the acetabular component for loosening. The other two patients developed delayed union or nonunion and both eventually required revision. The fractures in the two patients without revision healed and they had no requirement for subsequent revision. All eight patients had a stable prosthesis at a mean of 36 months after their latest revision procedure. 
Springer et al.260 reported seven displaced transverse periprosthetic acetabular fractures after uncemented acetabular revision about well-fixed components. Two were identified on routine radiographs, were asymptomatic, and were treated nonoperatively with a period of protective weight bearing and healed. Of the five symptomatic patients all were treated operatively. Four patients with the component well fixed to the superior portion of the ilium were treated with ORIF of the posterior column of the acetabulum without revision of the acetabular component. In one case where the cup was fixed to the inferior, ischial segment treatment was with a reconstruction cage. Of the five operatively treated fractures, one went on to nonunion and the other four healed and at the latest follow-up had a stable, well-fixed cup. 
Two patients in the series of Peterson and Lewallen with type II fractures had immediate revision of the acetabular component without adjuvant plate and screw fixation of the fracture.216 In one a cemented component was utilized and the fracture healed. The other was revised with a noncemented component with screw fixation through the shell. This patient went on to nonunion and required repeat revision with a cemented acetabular component and plate and screw fixation of the acetabular nonunion. Desai and Ries61 reported on two cases of likely missed intraoperative pelvic fractures associated with pelvic discontinuity in octogenarian patients with poor bone quality. This report emphasizes the importance of meticulous attention to bone preparation, appropriate underreaming for the socket, careful insertion, and awareness of potential fractures because the salvage for these fractures consists of extensive pelvic reconstruction. 

Author’s Preferred Treatment of Periprosthetic Acetabular Fractures

 
 

The optimal treatment of periprosthetic acetabular fractures is primarily dictated by component stability and fracture pattern stability (Fig. 23-1). In the setting of a stable component, stable fracture patterns are generally treated nonoperatively with protected weight bearing. Fracture patterns of this type include non- or minimally displaced anterior column fractures, fractures of the iliac wing, or medial wall fractures. Close follow-up, with weekly or biweekly radiographs are used to confirm progressive healing without secondary loss of reduction. Weight bearing is increased at about 6 weeks based on clinical and radiographic evidence of fracture healing.

 
Figure 23-1
Algorithm depicting the author’s preferred method of treatment for periprosthetic acetabular fractures.
Rockwood-ch023-image001.png
View Original | Slide (.ppt)
X
 

Surgical treatment with ORIF is preferred for management of unstable fractures about a stable acetabular component. Typical patterns of bony injury encountered in this scenario are displaced posterior column or transverse fractures. The fixation strategy, surgical approach, and implants are dictated by the details of the fracture pattern and generally follow those utilized for treatment of native acetabular fractures. Adjuvant bone grafts in these situations are generally not indicated.

 

In the setting of an unstable acetabular component, treatment requirements become much more complex. In such cases when there is a stable fracture pattern, revision of the acetabular component may be all that is required. In such cases, revision of the acetabular component with a press-fit shell utilizing multiple screw fixation on either side of the fracture may serve to provide a stable component as well as help stabilize the fracture. When the periprosthetic fracture involves both an unstable component and an unstable fracture pattern, the degree of bone loss should also be considered in the treatment algorithm. When there is no substantial bone loss, fixation of the unstable acetabular fracture as well as revision of the loose acetabular component is recommended. This usually takes the form of plating of the posterior column of the acetabulum. Revision also includes use of multiple screws preferably on either side of the major fracture line. In the setting of a pelvic discontinuity, reconstruction of the columns of the acetabulum may require substantial structural bone grafting with the possibility of the use of an acetabular cage. These cases represent some of the most challenging acetabular revisions and should be undertaken by an experienced surgical team with a substantial amount of necessary resources available.

Periprosthetic Femur Fractures about Hip Arthroplasty Prostheses

Incidence, Risk Factors, Prevention, and Mortality for Periprosthetic Femur Fractures About Hip Arthroplasty Prostheses

Vancouver A Periprosthetic Femur Fractures

Trochanteric fractures about hip arthroplasty stems, Vancouver type A fractures, can occur intraoperatively or postoperatively with similar frequency. They were found to occur intraoperatively in 21 of 373 (5.6%) patients operated on using a lateral approach with the patient in the supine position.112 All of these fractures occurred in women. Broach-only metaphyseal medial–lateral fit stems have a fracture rate that is technique dependent. Associated fractures usually involve the metaphyseal area and can be visualized within the surgical field along the medial aspect of the neck osteotomy. If there is an unrecognized intraoperative metaphyseal fracture, there is usually propagation and subsidence early in the postoperative period (Fig. 23-2). Postoperative fracture occurred in 2.6% of 887 cases treated with a single type of uncemented prosthesis.120 These fractures occurred through osteolytic cysts between 4 and 11 years after THA. 
Figure 23-2
An AP radiograph showing stem subsidence and hip dislocation after trochanteric periprosthetic fracture.
(Courtesy of Hari Parvataneni, MD.)
(Courtesy of Hari Parvataneni, MD.)
View Original | Slide (.ppt)
X

Vancouver B and C Periprosthetic Femur Fractures

Periprosthetic femoral shaft fractures are increasing in frequency because of the increasing number of patients with hip arthroplasties. The incidence of periprosthetic femur fracture after primary hip arthroplasty has been considered to be less than 1%,130,160,184 but has been reported to be as high as 2.3%.16,82,86,160 A recent survivorship analysis on 6,458 primary cemented femoral hip prostheses revealed a fracture incidence of 0.8% at 5 years and 3.5% at 10 years.46 Another series of 354 hips in 326 patients all treated with the same uncemented, straight, collarless tapered titanium stem and followed for a mean of 17 years showed a cumulative incidence of periprosthetic fracture of 1.6% at 10 years that increased to 4.5% at 17 years.263 The rate of fracture was low in the first 8 years after THA then increased into the second decade. In a comparison to the rate of aseptic loosening, the cumulative occurrence of periprosthetic fracture became equivalent to aseptic loosening at 17 years indicating the relative importance of periprosthetic fracture in the long term. 
After revision arthroplasty, the incidence of periprosthetic femoral shaft fractures climbs to between 1.5% and 7.8%.16,130,160,184,193 The risk further increases after an increasing number of revision surgeries.81 The lapsed time period from an index primary hip arthroplasty to periprosthetic femur fracture averages 6.3 to 7.4 years46,165 and is reduced to an interval of 2.3 years after a third revision procedure.165 
Risk factors for periprosthetic femoral shaft fractures about hip arthroplasty femoral stems are related to the age of the patient, gender, index diagnosis, presence or absence of osteolysis, presence or absence of aseptic loosening, primary or revision status, the specific type of implant utilized, and whether cemented or noncemented technique was utilized. Identifying risk factors can both improve patient counseling and potentially improve efforts at fracture prevention. 
Age, although commonly cited as a risk factor for periprosthetic femur fracture, is not clearly an independent risk factor.263 Coexisting medical comorbidities,255,256 osteoporosis,298 increased activity level,245 and fall risk also contribute. A recent report revealed a doubled risk of fracture in patients with higher medical comorbidities.255 Furthermore, the number of years after arthroplasty must be considered as each year after arthroplasty has been associated with a 1.01 additional risk ratio per year.81 
Although a higher proportion of periprosthetic femur fractures among female patients (52% to 70%) has been reported in many series,13,17,125,255,291 associated osteoporosis and a higher percentage of procedures being performed in female patients makes gender less clear as an independent risk factor. Accordingly, reports that account for such biases indicate no164,246,263 or even reduced risk for females.81 
The index diagnosis leading to arthroplasty may also be a risk factor with rheumatoid arthritis (RA) and arthroplasty for hip fracture each being identified as having increased risk ratios for fracture: RA having an increased ratio of 1.56 to 2.181,246 and hip fracture having a reported risk ratio of 4.4.246 
Osteolysis, especially near the tip of a loose femoral stem represents an impending pathologic fracture, a growing problem in arthroplasty, and a complex reconstructive challenge. Fracture, deficient bone stock, a loose implant, and an inciting particle generator may each need to be addressed during fracture repair and reconstruction. Osteolytic reaction associated with the use of a biodegradable cement restrictor has also been implicated as a potential etiologic factor.62 
Reports vary as to whether periprosthetic femur fracture is most often associated with a loose prosthesis. Some clinical data indicate that the presence of a loose stem represents a risk factor for subsequent fracture121,279 and other data show no such association.165,276 A cadaveric biomechanical comparison showed a 58% reduction in torsion to failure in specimens with loose as compared to those with well-fixed prostheses.106 
In the setting of revision hip arthroplasty, univariate and multivariate analyses of a large population of patients with postoperative periprosthetic fractures (n = 330) showed female gender, younger age, higher comorbidity index, and operative diagnosis associated with risk/hazard ratio of periprosthetic fracture.256 Women had a 66% higher risk than men, patients of age 61 to 80 had a 40% lower risk than those younger than 60, those with a Deyo–Charlston comorbidity index of 2 had 50% higher risk and those with an index of 3 or more had 100% higher risk than those with an index of 0. Operative diagnosis of nonunion and fracture was associated with a five-time higher risk of subsequent periprosthetic fracture. 
Intraoperative fracture has a unique subset of associated risk factors. During primary total hip or hemiarthroplasty, implantation of a cementless femoral component presents a reported 3% to 5.4% risk of intraoperative fracture compared to 0% to 1.2% for a cemented stem.16,79,102,250,271 The force utilized during insertion, the relative geometry of the stem and the femur, and the strength of the bone all may influence the risk of fracture during insertion of noncemented stems. Surgical experience helps dictate the required force for insertion. The “feel” and pitch of the sound made during each successive mallet blow are used to guide the experienced surgeon. Novel research has investigated the pitch and vibratory changes that occur as a potential means to minimize intraoperative fractures.185,241 Stem design also influences fracture rate and the surgeon must be aware of the unique aspects of each stem design and each patient’s femoral morphology which may predispose to fracture.37 Stems with a combination of metaphyseal and diaphyseal fit with a cylindrical diaphyseal design can predispose to diaphyseal fractures if the distal press fit is too aggressive or the reamers are not advanced to the full length of the stem (Fig. 23-3). Certain bone morphology patterns have been correlated with fracture during noncemented fixation47 because of a metaphysis–diaphysis mismatch. Cemented stems may also protect against postoperative fracture in patients with poor bone quality by virtue of internal stiffening of the femoral canal.275 
Figure 23-3
Cylindrical press-fit stems, especially when under reamed, pose a risk for fracture at the tip of the stem upon insertion as shown in this AP radiograph.
(Courtesy of Hari Parvataneni, MD.)
(Courtesy of Hari Parvataneni, MD.)
View Original | Slide (.ppt)
X
Impaction grafting for revision of a femoral hip component carries up to a 22.4% perioperative risk for fracture.73,188,236 Most of these fractures, many incidental perforations, have been found to occur with cement removal rather than the reconstructive procedure.73 Revision with large porous-coated diaphyseal stems have been reported to be associated with a nearly 30% risk,183 and long straight revision stems have an intermediate reported fracture occurrence of 18% with an additional 55% of cases thought to be at increased potential subsequent risk because of impingement of the distal stem tip on the anterior femoral cortex.305 
Patients with periprosthetic femur fractures have increased mortality.81 In multiple recent series, 7% to 18% of patients with periprosthetic fractures died within 1 year following surgical treatment.6,18,302 In one study, this mortality rate approached that of hip fracture patients (16.5%) treated during the same time period and was significantly higher than the mortality of patients undergoing primary joint replacement (2.9%).18 Data from the New Zealand National Registry indicated the 6-month mortality after revision THA associated with periprosthetic fracture (7.3%) was significantly higher than in a matched cohort undergoing revision for aseptic loosening (0.9%).302 

Fractures About Femoral Resurfacing Prostheses

Hip resurfacing arthroplasty is currently considered as a reasonable alternative to THA in a select patient population. Periprosthetic fracture during or after femoral resurfacing is a potentially devastating complication that requires abandonment of this arthroplasty technique and conversion to THA. The prevalence of periprosthetic fracture about hip resurfacing components has been identified as being approximately 1% in most studies but as high as 2.5%. Multiple large cohort studies have produced similar low short-term fracture rates. Fifty fractures were identified from 3,497 Birmingham hips inserted by 89 different surgeons (1.46%),254 five fractures were found in a series of 600 metal-on-metal surface arthroplasties (0.8%),5 and one fracture occurred in another series of 230 Birmingham hip resurfacings (0.4%).12 Another study of 550 cases revealed an overall fracture rate of 2.5%, but 12 of 14 fractures occurred in the first 69 resurfacing procedures performed by a single surgeon.173 After the first 69 cases, the incidence of fracture dropped to 0.4% demonstrating the importance of surgeon experience. It should be noted that long-term fracture rates remain largely unknown. Extrapolation of data for periprosthetic femoral shaft fractures about traditional femoral stems would indicate that these low rates of fracture about resurfacing implants may rise substantially at longer follow-up. However, the younger age of patients undergoing resurfacing may be protective against such a late rise in periprosthetic fracture rates. 
The risk of periprosthetic fracture has been tied to subtle aspects of surgical technique, bone quality, and patient selection. Notching of the superior aspect of the femoral neck, a varus position of the femoral component, and inadequate coverage of the reamed portion of the femoral head have each been implicated as surgeon-controlled risk factors for periprosthetic fracture5,254 that may be present in up to 85% of these fractures.254 Biomechanical analyses support the clinical findings that a valgus orientation decreases the risk of femoral neck fracture169,231 and suggested that maximum valgus, while avoiding notching, may provide maximum protection from periprosthetic fracture.231 Poor bone quality has been subjectively described as a risk factor for periprosthetic fracture.191 This theory is supported by biomechanical investigation, but bone quality was found to be less important than varus–valgus orientation of the component.9 A change in indications was one factor attributed to a reduction in femoral neck fracture rate from 7.2% to 0.8% although the specific changes were not detailed and technique modifications occurred simultaneously. The technical aspects may have been largely responsible for the reduced fracture rate seen.191 Another study suggested that female gender and obesity may be patient-related risk factors for fracture.173 

Classification of Periprosthetic Femur Fractures About Hip Arthroplasty Prostheses

Classification of Postoperative Periprosthetic Femur Fractures

The Vancouver classification is most useful to direct communication about and treatment of periprosthetic femoral shaft fractures about hip arthroplasty stems.64 Its reliability and validity have been confirmed and therefore it represents the current standard for assessing and reporting these fractures.25,64,88,198,225 It considers the location of the fracture relative to the stem, the stability of the implant, and associated bone loss (Fig. 23-4). Type A fractures are in the trochanteric region, type B fractures involve the area of the stem, and type C fractures are distal to the tip of the stem such that their treatment is considered independent of the hip prosthesis (except relating to overlap of the fixation device and the prosthesis). Type A fractures are subdivided into fractures of the greater trochanter, AG (Fig. 23-5), and the much less common fractures about the lesser trochanter, AL. Type B fractures are also further subdivided: B1 fractures are associated with a stable implant, B2 fractures are associated with a loose implant, and B3 fractures are associated with bone loss and usually a loose implant (Table 23-5). The ability to distinguish a well fixed from a loose implant in the setting of periprosthetic fracture may be difficult; therefore intraoperative testing of implant stability and preparation for dealing with a loose stem are prudent.225 
Figure 23-4
Vancouver classification for periprosthetic fractures about femoral hip arthroplasty stems.
 
Type A fractures are subdivided based on fracture location at the greater trochanter (Type AG) or at the lesser trochanter (Type AL). Type B fractures are subdivided based on presence of a well-fixed stem (Type B1), a loose stem (Type B2), or poor bone stock in the proximal fragment (Type B3). Type C fractures are distal to stem tip.
Type A fractures are subdivided based on fracture location at the greater trochanter (Type AG) or at the lesser trochanter (Type AL). Type B fractures are subdivided based on presence of a well-fixed stem (Type B1), a loose stem (Type B2), or poor bone stock in the proximal fragment (Type B3). Type C fractures are distal to stem tip.
View Original | Slide (.ppt)
Figure 23-4
Vancouver classification for periprosthetic fractures about femoral hip arthroplasty stems.
Type A fractures are subdivided based on fracture location at the greater trochanter (Type AG) or at the lesser trochanter (Type AL). Type B fractures are subdivided based on presence of a well-fixed stem (Type B1), a loose stem (Type B2), or poor bone stock in the proximal fragment (Type B3). Type C fractures are distal to stem tip.
Type A fractures are subdivided based on fracture location at the greater trochanter (Type AG) or at the lesser trochanter (Type AL). Type B fractures are subdivided based on presence of a well-fixed stem (Type B1), a loose stem (Type B2), or poor bone stock in the proximal fragment (Type B3). Type C fractures are distal to stem tip.
View Original | Slide (.ppt)
X
Figure 23-5
A minimally displaced fracture of the greater trochanter (Vancouver type AG) that occurred postoperatively.
Rockwood-ch023-image005.png
View Original | Slide (.ppt)
X
Table 23-5
Vancouver Classification Scheme and Treatment Options for Postoperative Fractures
Trochanteric Diaphyseal Distal to Stem
Classification AL AG B1 B2 B3 C
Bone Stock Good Good Good Good Poor Good
Stem Fixation Well fixed Well fixed Well fixed Loose Loose Well fixed
Author’s Preferred Treatment Options Symptomatic treatment unless substantial medial cortex is involved Symptomatic treatment or ORIF with claw plate to treat pain, weakness, limp, or instability Lateral plate applied with biologic fracture reduction techniques. Consider extending plate to include lateral femoral condyle Uncemented revision long stem with or without lateral plate Long stem revision with allograft with or without a lateral plate or revision to a tumor prosthesis Distal femoral locking plate extending proximal to overlap the femoral stem
X

Classification of Intraoperative Periprosthetic Femur Fractures

The original Vancouver classification was developed to describe postoperative fractures but has been expanded to address intraoperative periprosthetic femur fractures.177 Similarly to the original, the intraoperative Vancouver classification divides fractures into three zones: Type A being of the proximal metaphysis without extension to the diaphysis, type B are diaphyseal about the tip of the stem, and type C fractures extend beyond the longest revision stem and include fractures of the distal metaphysis. The subclassification of each type distinguishes the intraoperative from the postoperative classification and reflects fracture stability: Subtype I represents a simple cortical perforation; subtype II is a nondisplaced linear cortical crack; and subtype III is a displaced or otherwise unstable fracture (Table 23-6). The treatment options for fractures occurring intraoperatively vary somewhat based on when the fracture was detected. Intraoperative identification, in general, leads to more surgical interventions than identification in the recovery room or later (Table 23-6). 
Table 23-6
Vancouver Classification Scheme and Treatment Options for Intraoperative Fractures
Metaphyseal Diaphyseal Distal to Stem
Classification A1 A2 A3 B1 B2 B3 C1 C2 C3
Fracture Morphology Cortical perforation Undisplaced crack Displaced or unstable Cortical perforation Undisplaced crack Displaced or unstable Cortical perforation Undisplaced crack Displaced or unstable
Author’s Preferred Treatment Options
Recognized Fractures Protected weight bearing or bone graft Protected weight bearing or cerclage cables ORIF with claw plate with conversion to long stem if implant unstable Cortical strut with or without conversion to long stem implant Lateral plate with conversion to long stem if implant unstable Lateral plate with conversion to long stem if implant unstable Cortical strut Lateral plate Lateral plate
Unrecognized Fractures Protected weight bearing Protected weight bearing ORIF with claw plate with revision to long stem if implant unstable Cortical strut Lateral plate with revision to long stem if implant unstable Lateral plate with revision to long stem if implant unstable Cortical strut Protected weight bearing or lateral plate Lateral plate
X

Classification of Periprosthetic Femur Fractures After Hip Resurfacing

No universally accepted or tested classification of periprosthetic femoral fractures associated with hip resurfacing currently exists. A systematic analysis of 107 specimens retrieved at the time of revision hip arthroplasty because of periprosthetic fracture revealed three distinct fracture patterns.309 Type A were described as biomechanical fractures, type B as acute postnecrotic fractures, and type C chronic biomechanical fractures. Type A fractures occurred at an average of 41 days postoperatively. They were characterized by changes consistent with acute fracture without signs of osteonecrosis, regenerative fibrosis, or vascular proliferation. Type B fractures occurred at an average of 149 days postoperatively and all of these fractures were associated with osteonecrosis. Type C fractures were seen at an average of 179 days postoperatively. These were characterized by evidence of refracture or pseudoarthrosis through a previous fracture. Fractures were also categorized based on the location of the fracture, inside or outside the bounds of the edge of the femoral head component. The majority occurred inside the femoral component (59%). All acute biomechanical fractures were located exclusively outside of the component and were located in the neck. 

Management Principles for Periprosthetic Femur Fractures

Management Principles for Vancouver Type A Periprosthetic Femur Fractures

The majority of periprosthetic fractures of the greater trochanter, Type AG, are stable. They are usually nondisplaced or minimally displaced and are stabilized by the opposite pull and continuity of the soft tissue sleeve connecting the abductors and the vastus lateralis.281 Such stable fractures when occurring postoperatively can be managed nonoperatively with symptomatic treatment. Weight bearing to tolerance is generally allowed. Intraoperative stable fractures of the greater trochanter can be managed similarly especially when recognized after wound closure. When recognized intraoperatively internal fixation may be considered. Nonoperative treatment is contraindicated if there is a complete fracture of the greater trochanter including the abductor attachment without a stabilizing soft tissue sleeve as the chance of migration, nonunion, and hip instability is high. In addition, if stability of the implant is compromised, or if the patient is unable to comply with abductor restrictions during the healing process, nonoperative treatment is not recommended. 
Protected weight bearing may be used for nondisplaced or incomplete fractures about hip stems or resurfacing implants that are recognized after surgery. Typically, partial or toe-touch weight bearing is recommended with a walker or crutches. Abductor precautions can be added to protect nondisplaced greater trochanter fractures. The use of a walking device to unload the abductors during gait as well as avoidance of abductor strengthening or active abduction exercises is recommended while these fractures heal. It is important to obtain regular imaging using similar radiographic projections with increased frequency in the early post-op period. This will monitor displacement and allow decisions for continued observation or operative intervention if there is fracture displacement or loss of implant stability. 
Widely displaced, or otherwise unstable fractures of the greater trochanter (Vancouver Type AG), especially when associated with substantial pain, weakness, or limp, are generally treated operatively with ORIF typically with a claw plate that engages the soft tissue attachment of the gluteus medius as well as the bone of the greater trochanter (Fig. 23-6). Results with these modern plates represent an improvement over other techniques.165,166 Fractures of the lesser trochanter, Vancouver type AL, are typically avulsion fractures that can be managed nonoperatively. However, larger fractures that involve a segment of the proximal medial femoral cortex are typically associated with tapered press-fit stem designs and are usually treated operatively with cerclage cables or wires with or without revision of the stem to one that provides fixation distal to the fracture.282 Nondisplaced fractures of this nature noted intraoperatively can be managed with cerclage cables with retention of the femoral stem if stable. Displaced medial fractures noted intraoperatively or postoperatively are managed with cables and revision to a stem with distal fixation. 
Figure 23-6
A fracture of the greater trochanter (Vancouver AG) treated with a small buttress plate and lag screws that resulted in nonunion (A) is successfully treated with a claw plate (B).
Rockwood-ch023-image006.png
View Original | Slide (.ppt)
X

Management Principles for Vancouver Type B Periprosthetic Femur Fractures

Vancouver type B fractures identified during surgery are rarely treated nonoperatively. Those recognized postoperatively can be treated nonsurgically in certain cases (Table 23-7). If there is excellent implant stability and the fracture is incomplete or a nondisplaced diaphyseal crack, these can be observed with protected weight bearing and close follow-up. In addition, if there is adequate distal stem fixation and a strictly proximal fracture, this can be observed. If there is a high predicted chance of stem subsidence or fracture displacement, operative management should be pursued early. This is typically the case with proximal (metaphyseal) fit stems with an intraoperative metaphyseal fracture where the risk of fracture propagation and stem subsidence is high. 
Table 23-7
Periprosthetic Femur Fractures About Hip Arthroplasty Prostheses
Nonoperative Treatment
Indications Relative Contraindications
Stable femoral stem and nondisplaced diaphyseal fracture Loose implant
Proximal fracture related to osteolysis with adequate distal stem fixation Proximal metaphyseal fracture with a proximal fit stem
Nondisplaced neck fracture associated with hip resurfacing Displaced diaphyseal or distal fracture
Minimally displaced trochanteric fracture Widely displaced greater trochanteric fracture with altered abduct or function
X
The difficulty in operative management of periprosthetic femoral shaft fractures that involve the tip of hip arthroplasty stems, Vancouver type B fractures, is evidenced by the array of treatment options described without a clear consensus emerging on the most appropriate method.140,160 Operative treatment of these femur fractures is indicated in most circumstances, except for those fractures that are truly nondisplaced or when the patient’s condition prohibits operation. ORIF with plates and revision arthroplasty with or without supplementary autologous or allogeneic bone grafting are the most common methods for operative stabilization.39,99,222 Stabilization using ORIF techniques with plates and screws or cortical onlay allografts or a combination of both is indicated for femoral shaft fractures about well-fixed implants (Vancouver type B1 fractures).24,98,276,294 Historically, there has been little role for revision arthroplasty for B1 fractures given the stable prosthesis. However, revision of an associated well-fixed stem to a long stem modular prosthesis nail that spans the fracture has recently been advocated by multiple authors for Vancouver B fractures regardless of stem stability.149,151,210 The earlier weight bearing and improved mobilization associated with revision arthroplasty with implants that span the fracture may provide for improved mortality rates if patients who can withstand the magnitude of such surgery are properly selected. Femoral component revision with or without adjuvant plate and/or allograft strut fixation is indicated for Vancouver types B2 and B3 fractures where the femoral stem is loose. The indication for including allograft struts in the operative strategy is most clear when there is associated bone loss from long standing component motion, type B3 fractures. 
For femoral shaft fractures around a loose implant, Vancouver types B2 and B3 fractures, revision of the femoral component is typically recommended (Fig. 23-7). This strategy addresses both the loose component and the fracture and provides intramedullary stability by virtue of longer femoral stems used for revision. Fracture fixation with a lateral plate or reconstitution of bone stock with allograft strut or sometimes a combination of both plates and struts are utilized in addition to femoral component revision. In more severe cases of bone loss, an allograft prosthesis composite, impaction bone grafting technique, or proximal femoral replacement may be considered.153,194 Knowledge of specific revision techniques is necessary to effectively handle these challenging cases. In addition to the above mentioned radiographic evaluation of the fracture and femoral stem stability, quality orthogonal radiographs are also mandatory to evaluate the fixation status of the acetabular component and remaining acetabular and femoral bone stock. If possible, the operative note from the original arthroplasty should be obtained to determine the manufacturer of the components, so that new acetabular liners, if needed, can be available. The presence of prefracture hip symptoms, such as mechanical thigh or groin pain, can alert the surgeon to potential component loosening, if the radiographs are equivocal. Serologies such as sedimentation rate and C-reactive protein are of unknown benefit in the presence of an acute fracture. If there is any concern for infection, a preoperative hip aspiration should be considered. 
Figure 23-7
Fracture about a loose hemiarthroplasty stem with good bone stock (Vancouver B2) (A) is treated with a long porous-coated revision stem and lateral plating (B) that protects the entire length of the femur.
Rockwood-ch023-image007.png
View Original | Slide (.ppt)
X

Management Principles for Vancouver Type C Periprosthetic Femur Fractures

In the initial description of the Vancouver classification type C fractures were described as those “well distal” to the stem.64 It has been inferred that treatment indications and fixation techniques for these fractures are independent of the femoral prosthesis. This, however, is an oversimplification of the typical situation. Distal femoral shaft fractures in the absence of a hip prosthesis are typically treated with intramedullary nails (either antegrade or retrograde) and supracondylar or intercondylar fractures are treated with either a lateral plate or retrograde nail. Vancouver type C periprosthetic fractures, by virtue of the femoral stem, obviate standard techniques and implants utilized for nailing of native femoral shaft fractures. Attempts to insert standard retrograde nails in this short segment are ill advised because of inadequate fixation within the proximal fragment and propensity for nonunion187 and malunion (Fig. 23-8). A unique retrograde nail designed to slide over the tip of the femoral stem has shown reasonable results as described in a small clinical series and has been studied in a biomechanical analysis that supports immediate weight bearing with this device.310,311 ORIF remains the most applicable method of internal fixation. Ending a plate at or just distal to the femoral stem should also be avoided to minimize the stress rise effect (Fig. 23-9). Instead, the plate should span the fracture and overlap the zone of the stem (Fig. 23-10). The indications and contraindications for surgical management follow closely those for Vancouver type B Fractures. Additional principles and results of treating these distal femoral shaft fractures and metaphyseal fractures are presented in Chapter 52 Femoral Shaft Fractures and Chapter 53 Distal Femoral Fractures
Figure 23-8
 
A: Ill-advised treatment of a Vancouver Type C femur fracture distal to a hip arthroplasty stem. B: The nail eroded through the anterior cortex and a nonunion developed. This was treated with nail removal, ORIF with a lateral plate, autologous bone graft to stimulate nonunion healing, and an anterior strut graft to restore bone stock.
A: Ill-advised treatment of a Vancouver Type C femur fracture distal to a hip arthroplasty stem. B: The nail eroded through the anterior cortex and a nonunion developed. This was treated with nail removal, ORIF with a lateral plate, autologous bone graft to stimulate nonunion healing, and an anterior strut graft to restore bone stock.
View Original | Slide (.ppt)
Figure 23-8
A: Ill-advised treatment of a Vancouver Type C femur fracture distal to a hip arthroplasty stem. B: The nail eroded through the anterior cortex and a nonunion developed. This was treated with nail removal, ORIF with a lateral plate, autologous bone graft to stimulate nonunion healing, and an anterior strut graft to restore bone stock.
A: Ill-advised treatment of a Vancouver Type C femur fracture distal to a hip arthroplasty stem. B: The nail eroded through the anterior cortex and a nonunion developed. This was treated with nail removal, ORIF with a lateral plate, autologous bone graft to stimulate nonunion healing, and an anterior strut graft to restore bone stock.
View Original | Slide (.ppt)
X
Figure 23-9
Ill-advised treatment of a Vancouver Type C fracture with a plate that is too short because it creates an unnecessary additional stress riser at the tip of the arthroplasty stem.
Rockwood-ch023-image009.png
View Original | Slide (.ppt)
X
Figure 23-10
A Vancouver C fracture (A) treated with an optimal plate construct (B) that spans the fracture, the zone of the femoral stem, and the entire unprotected femur distally.
Rockwood-ch023-image010.png
View Original | Slide (.ppt)
X

Management Principles for Fractures About Femoral Resurfacing Prostheses

Nonoperative management is often cited as a viable treatment option for nondisplaced femoral neck fractures associated with hip resurfacing.50,54,123 Fractures that are completely displaced or those with components that have shifted are generally treated with revision arthroplasty. 
Although nonoperative management has been described for nondisplaced fractures of the femoral neck associated with hip resurfacing,50 revision to a conventional THA is typically performed.5,173,309 There is little role for internal fixation of these femoral neck fractures after resurfacing, although successful plate and screw fixation and intramedullary nailing (IMN) has been reported for management of intertrochanteric and subtrochanteric fractures in the setting of hip resurfacing.33,212 

ORIF of Periprosthetic Femur Fractures

Indirect fracture reduction techniques have favorable biologic features that minimize soft tissue disruption, preserve the vascular supply to bone, enhance healing, and decrease the incidence of nonunion for many fractures including periprosthetic femur fractures,116 often obviating the need for supplemental bone grafting.227 Successful application of these techniques to periprosthetic fractures must consider the fracture location relative to the femoral component, the implant stability, the quality of the surrounding bone, and the medical and functional status of the patient.64 The following are principles for ORIF of periprosthetic femoral shaft fractures about hip arthroplasty stems, Vancouver type B. These general principles also apply for Vancouver types A and C fractures. Subtleties in technique and differences in implant choices distinguish techniques for Vancouver types A and C fractures. 

Preoperative Planning for ORIF of Periprosthetic Femoral Fractures

When ORIF of periprosthetic femur fractures is planned, the surgeon should be prepared for encountering an unexpected intraoperative finding of a loose femoral component (Table 23-8). Radiographically stable implants may be loose in up to 20% of cases of B1- and C-type fractures.49 Therefore, all aspects of the preoperative plan should allow for the contingency that revision arthroplasty may be required. A radiolucent OR table is required and although ORIF can be performed with the patient in the supine or lateral position, the lateral position is preferred to accommodate the possibility of revision arthroplasty via a posterior approach. A radiolucent positioner, such as a beanbag, is required. It should be noted that positioners, such as peg boards, used for hip arthroplasty may not be radiolucent. Fluoroscopic access to the entire limb and hip should be planned for. The equipment needed for ORIF of periprosthetic femur fractures can be extensive to accommodate all contingencies: ORIF, revision of the femoral stem, revision of the acetabular component, strut grafting, and autologous bone grafting (Table 23-8). Similarly, the implants required for these contingencies should be confirmed to be readily available. 
Table 23-8
ORIF of Periprosthetic Femoral Fractures About Hip Arthroplasty Stems
Preoperative Planning Checklist
  •  
    OR table: Radiolucent table that allows fluoroscopic imaging of the entire involved femur and hip
  •  
    Position/positioning aids: Lateral decubitus using a radiolucent positioner such as a beanbag (peg boards are typically not radiolucent) or supine
  •  
    Fluoroscopy location: Opposite side from the primary surgeon’s position with the monitor at the foot
  •  
    Equipment:
    •  
      An array of reduction forceps
    •  
      Burr
    •  
      Sagittal saw
    •  
      Cable set
    •  
      Equipment required for revision arthroplasty should be immediately available
  •  
    Implants:
    •  
      Large fragment set
    •  
      Straight or bowed plates (or specialty plates) long enough to span the entire femur
    •  
      At least six cables (approximately 1.7-mm diameter)
    •  
      Femoral allograft strut
    •  
      Implants required for revision arthroplasty should be immediately available
    •  
      For Vancouver Type A fractures, specialized trochanteric “claw” plates are typically needed rather than long plates that span the entire femur
  •  
    Tourniquet (sterile/nonsterile): None required
  •  
    Blood: PRBCs typed and crossmatched
X

Surgical Approach for ORIF of Periprosthetic Femur Fractures

For ORIF of periprosthetic femoral shaft fractures, a straight lateral thigh incision is used for exposure of the lateral aspect of the femur. Posterior incisions from prior hip arthroplasty are incorporated. Dissection is carried down to the iliotibial fascia with care to minimize stripping of the subcutaneous fat from the fascia. Self-retaining retractors are not utilized until they can be placed at a fascial level. The iliotibial fascia is incised parallel to its fibers and the fascia of the vastus lateralis is also incised parallel to its fibers approximately 3 cm from its attachment to the intermuscular septum. The vastus lateralis muscle is carefully elevated off the posterior fascial flap and retracted anteriorly. This is done in a distal to proximal motion based on the orientation of the muscle fibers attachment to the fascia. Dissection done in this manner takes advantage of the axilla created between the muscle fibers and the fascia and allows the muscle to be elevated cleanly off the fascia. Perforating vessels are identified and ligated as needed. Meticulous deep soft tissue dissection is used to minimize devascularization of bone. Exposure is limited to the lateral surface of the femur spanning the region needed to apply and secure a plate proximal and distal to the fracture. Whenever possible, the muscle is left undisturbed in the region of the fracture and the plate slid in an extraperiosteal plane deep to the muscle in this region. When direct access to the fracture is required, to remove entrapped soft tissue for instance, great care is taken to work through the fracture site rather than to strip muscle from around the bone. 

Reduction Strategy for ORIF of Periprosthetic Femur Fractures

Once adequate exposure is obtained, and hemostasis assured, attention is turned to fracture reduction and fixation. The reduction technique is distinct based on the fracture pattern. Either an anatomic reduction and rigid fixation (lag screws or compression plating or both) (Table 23-9) or a bridge plating technique is chosen (Table 23-10). The simple patterns typically seen with these fractures are amenable to the anatomic reduction and rigid fixation strategy. This strategy can easily lead to inadvertent excessive soft tissue stripping more so than a bridge plating technique. Therefore, great care and patience during reduction maneuvers is required. Although cerclage cables have a reputation of being associated with excessive soft tissue stripping, this is not absolute. Properly and carefully placed cables can ease the effort of reduction, especially with the long oblique or spiral fractures that are commonly encountered. The afforded ease of reduction that cables provide can actually reduce soft tissue disruption associated with prolonged and repeated reduction attempts without cables. The cables and any adjunctive clamps are placed through muscle rather than underneath muscle. This strategy sacrifices very few muscle fibers and minimizes subperiosteal stripping and has been employed successfully in clinical series.227,300 When a bridge plating construct is utilized, when there is fracture comminution, a properly contoured plate is used as a reduction template for alignment in the coronal and sagittal planes. The surgeon then only needs to assure proper length. Because, with this strategy, individual fracture fragments do not require anatomic reduction, the risk of excessive iatrogenic stripping should be minimal. 
Table 23-9
ORIF of Simple Periprosthetic Femoral Shaft Fractures About Hip Arthroplasty Stems (Vancouver Types B and C)
Surgical Steps
  •  
    Expose the lateral femur
  •  
    Debride displaced fractures without causing unnecessary soft tissue stripping
    •  
      For comminuted fractures, this step is neither required nor advised
  •  
    Reduce the fracture incrementally with manual traction and gentle manipulation
    •  
      Provisional cable fixation of spiral oblique fractures to help obtain and maintain reduction
    •  
      Goal is an anatomic reduction
  •  
    Apply precontoured lateral plate
    •  
      Consider spanning entire length of the femur to protect from subsequent peri-implant fractures
    •  
      Plate should be contoured to match the lateral femur
  •  
    Provisionally secure plate to the proximal fragment with cables
  •  
    Provisionally secure plate to distal fragment with nonlocked screws
  •  
    Apply lag screw across fracture through plate, if possible
  •  
    Loosen provisional fixation and lag screw enough to remove initial reduction cable from beneath plate
    •  
      This step is optional, as reduction cable can be left beneath plate
  •  
    Finally tighten distal screws
  •  
    Finally tighten lag screw
  •  
    Sequentially tighten proximal cables
    •  
      Finally secure cables once all cables are sufficiently and equally tightened
  •  
    Add additional screws into greater trochanter and distal fragment as necessary
    •  
      Consider locked screws
X
Table 23-10
ORIF of Comminuted Periprosthetic Femoral Shaft Fractures About Hip Arthroplasty Stems (Vancouver Types B and C)
Surgical Steps
  •  
    Expose the lateral femur
  •  
    Avoid disruption of the comminuted fracture zone. Formal debridement of fracture fragments is unnecessary.
  •  
    Apply precontoured lateral plate
    •  
      Consider spanning entire length of the femur to protect from subsequent peri-implant fractures
    •  
      Plate should be contoured to match the lateral femur
    •  
      Fracture reduction is not required at this step
  •  
    Provisionally secure plate to the proximal fragment with cables
  •  
    Re-establish length and rotation
  •  
    Finally secure plate to distal fragment with nonlocked screws
    •  
      Coronal plane alignment is restored by using the plate contour as a reduction aid
    •  
      Sagittal plane alignment is restored by having the plate centered on the proximal and distal fragments on a lateral x-ray view
  •  
    Sequentially tighten proximal cables
    •  
      Finally secure cables once all cables are sufficiently and equally tightened
  •  
    Add screws into greater trochanter and distal fragment as necessary
    •  
      Consider locked screws
X
For typical spiral fractures, the first step is to restore gross alignment and length. The latter requires complete muscle relaxation. With complete paralysis, manual longitudinal traction by an assistant can usually restore length, at least to within 2 to 3 cm upon the first attempt. The fracture is provisionally stabilized with pointed reduction clamps. Anatomic reduction need not be accomplished all at once prior to initial clamping of the reduction. Rather, reduction is accomplished with stepwise improvements. Residual deformity at each step is identified via direct vision, palpation, and/or fluoroscopy and requirements for successive reduction maneuvers determined. During these maneuvers, great care is taken not to inadvertently strip soft tissue. The orientation of clamps is critical. To hold an established reduction, clamps placed perpendicular to the fracture work well. However, clamps used to help obtain a reduction are not necessarily placed perpendicular to the fracture plane. They are placed in an orientation such that squeezing the clamps will provide a force vector that serves to better reduce the fracture. Once the reduction is close, within about 1 cm in length, one or two cables are passed around the fracture and provisionally tightened. Two cables are used for longer oblique fractures. The cable tension can be relaxed to afford final reduction maneuvers, typically rotation and additional traction via appropriately placed clamps or via manual traction of an assistant. Once the fracture has “keyed in” and the reduction is confirmed with fluoroscopy, the cables are definitively retensioned. 

Fixation Technique for ORIF of Periprosthetic Femur Fractures

ORIF Technique for Vancouver A Fractures.
Claw plates are typically used for fixation of greater trochanteric fractures. The tines of the claw are placed through the tendinous insertion of the gluteus medius and impacted into the tip of the trochanter thereby gaining soft tissue and bony purchase proximally. A plate is selected to bypass the apex of the fracture by enough distance to apply two to three well-spaced (approximately 2 cm apart) cables around the zone of the femoral stem. A vertically applied cable is recommended to augment the claw fixation proximally. There is usually no requirement to extend the plate beyond the tip of the femoral prosthesis. However, very short plates have been associated with fixation failure.166 Of course, the stability of the arthroplasty components is considered, and when loose they are revised. When these fractures are associated with substantial osteolysis, bone grafting is indicated with care to maintain the soft tissue stabilizers.281 
ORIF Technique for Vancouver B and C Fractures.
The preferred plate construct for Vancouver type B1 fractures includes a lateral plate contoured proximally to accommodate the trochanteric flare. Distally, the plate should have a minimum of six to eight holes covering the native femur distal to the fracture or extend to the condylar region (where a distal femoral plate design may be utilized). A bowed plate to accommodate the sagittal bow of the femur is preferred. When the strategy for fracture reduction includes provisional fracture fixation with cables, plate fixation of the reduced fracture is very simple; however, several principles should be adhered to. A well-contoured plate can be secured to either the proximal and distal fragment with cables or nonlocked screws without affecting the reduction. However, when the plate contour deviates from the bone contour, nonlocked screws and cables can potentially disrupt an anatomic reduction. In such circumstances, additional efforts to contour the plate anatomically are advised, especially with regard to the proximal fragment where nonlocked means, primarily cables, are the primary method of fixation. Deviations between the distal fragment and distal plate contour can be accommodated with the use of locked screws without disrupting a pre-established anatomic reduction. When the fracture pattern allows, a lag screw distal to the stem and across the fracture is utilized (Table 23-9). Screws through an existing cement mantle, either in the proximal or distal fragment, provide excellent points of fixation. If such a screw can be placed in the proximal fragment, this screw is tightened prior to definitive tensioning of cables. Three or more equally spaced cables are used proximally between the lesser trochanter and the tip of the stem. Devices to attach or hold cables to the plate are not required; the cables are simply passed around the plate with the crimping connection purposely positioned either just anterior or just posterior to the plate to minimize prominence and to allow easy access for locking the cable. The cables are individually tightened and provisionally secured, then retightened sequentially akin to the method of tightening lug nuts on a car wheel. This assures that tightening one cable does not result in loosening of an adjacent cable. A recent study indicates that cerclage wires and cables provide point contact fixation and are unlikely to strangulate blood supply.154 Screws, typically locked screws, are placed in the trochanteric region after all cables are tensioned. 
Proximal fragment screw fixation without the use of cables has been successfully employed.28,66 With this strategy, multiple short locked screws are supplemented with bicortical locked screws into the trochanteric region or around the stem or both. To increase the screw density in the trochanteric region, reversed application of plates designed for the distal femur have been utilized.66,70 Isolated use of unicortical locked screws is not recommended because of marginal rotational control. 
Several considerations go into distal fixation details: the plate length covering the distal segment, the location of screws, the number of screws, and the type of screws. The minimum plate length to obtain satisfactory distal fixation usually corresponds to six plate holes but this minimum threshold is increased when poor quality bone is encountered. Longer plates that extend to the lateral femoral condyle have recently been advocated to protect the entire femur (Fig. 23-11) and reduce the risk of subsequent peri-implant fracture at the distal margin of the plate (Fig. 23-12).229 This strategy is at the expense of an increased risk of plate-related pain over the subcutaneously located condylar extent of the plate. The holes nearest to the fracture and farthest from the fracture are the most important for maximizing construct stability. These holes and two in between are typically filled with screws. Locked or additional screws should be considered when osteoporotic bone is present. When nonlocked screws could cause a malreduction because of plate and bone contour mismatch, locked screws should be utilized. In general, locked screws should be placed after nonlocked screws and appear to be most advantageous near to the fracture. The initially placed reduction cables can either be left under the plate or removed from beneath the plate after two points of provisional fixation are established in both the proximal and distal fragments. These provision points of fixation, cables and screws, must be loosened slightly to allow cable removal from beneath the plate. 
Figure 23-11
AP view of a modern modification of the Ogden construct with a long distal femoral plate to protect the entire femur and with locked screws to augment fixation.
Rockwood-ch023-image011.png
View Original | Slide (.ppt)
X
Constructs that span the entire femur avoid such complications.
View Original | Slide (.ppt)
Figure 23-12
A Vancouver Type B femur fracture treated successfully with a lateral plate until fracture occurred at the distal tip of the plate.
Constructs that span the entire femur avoid such complications.
Constructs that span the entire femur avoid such complications.
View Original | Slide (.ppt)
X
Strut allografts are reserved for situations with associated bone loss (Vancouver B3 fractures). The strut is secured anteriorly with cables placed proximal and distal to the fracture. These are a combination of cables independent of an associated plate (cables over the strut and under the plate) and with cables around both the plate and strut. 
When fractures of the medial calcar are noted intraoperatively, x-rays are obtained to delineate the extent of fracture, as occasionally these splits can spiral down toward the stem tip. Limited, nondisplaced medial cracks noted intraoperatively are treated with one or two cerclage cables. When propagation is present, a lateral plate is used to bypass the distal extent of the fracture. Displaced fractures of either the lesser or greater trochanter are treated operatively with an anatomic ORIF. Limited sized lesser trochanteric fractures are treated with cables alone. 
Vancouver type C fractures were originally defined as being “well distal” to the femoral stem. These are usually in the supracondylar femur region and are occasionally intercondylar. Although the fracture fixation is not entirely dictated by the presence of the femoral stem, the femoral stem must be considered. There is almost always not enough proximal shaft bone to allow stable fixation of a retrograde nail. The mainstay of treatment of distal femur fractures in the presence of a femoral stem is ORIF with lateral plates. The principles for lateral plating (LP) for Vancouver C fractures are similar to those for Vancouver B fractures. Locked plates are used to provide fixed-angle stability of the end segment and improved fixation in an osteoporotic shaft segment. The main deviation from standard fixation of these fractures because of the presence of the hip arthroplasty stem comes with fixation proximally. It is rare that a lateral plate used to provide stable fixation of the distal femur fracture is short enough to avoid creating a stress riser effect between the top of the plate and the hip arthroplasty femoral stem. Therefore, we recommend that plates utilized for Vancouver type C fractures be long enough to overlap the femoral stem. Fixation in the proximal fragment is with multiple screws distal to the stem into the native shaft fragment and supplemented with two cables around the plate in the zone of the femoral prosthesis. This construct provides satisfactory stability for fixation of the distal femur fracture and protects the entire femur from future fracture. 

Postoperative Care for ORIF of Periprosthetic Femur Fractures

Postoperatively, early rehabilitation is concentrated on mobilization and knee ROM. Weight bearing is protected to some degree for approximately 6 to 8 weeks. Initial weight-bearing restrictions are typically toe-touch for balance or up to 50% weight bearing if the bone quality and fixation were both optimal. Immediate weight bearing has been advocated after minimally invasive plate application;68,69 however, little clinical results to support such an aggressive protocol are available. Therapy for knee ROM, transfer training, and use of assist devices are initiated immediately postoperatively. Based on progressive clinical and radiographic signs of fracture healing, weight bearing is gradually advanced. Full weight bearing is typically accomplished by 6 to 8 weeks and at this time formal strengthening and gait training therapy are useful. 

Potential Pitfalls and Preventative Measures for ORIF of Periprosthetic Femur Fractures

ORIF of periprosthetic femoral shaft fractures are demanding procedures (Table 23-11). These fractures are most commonly simple spiral oblique fracture patterns. They are therefore, typically amenable to anatomic reduction with compression techniques. To obtain anatomic reduction it is often possible to inadvertently strip substantial amounts of soft tissues. The surgeon must be continually aware of this potential problem and should adhere to biologic fracture fixation techniques. The use of cables to provisionally obtain and hold a reduction of long spiral fractures can actually make the reduction process easier and may limit soft tissue stripping if properly applied (Fig. 23-10B). Cables should be passed through muscle rather than circumferentially under the muscle. 
 
Table 23-11
ORIF of Periprosthetic Femoral Shaft Fractures
View Large
Table 23-11
ORIF of Periprosthetic Femoral Shaft Fractures
Potential Pitfalls and Preventions
Pitfalls Preventions
Extensive soft tissue stripping during reduction Adherence to biologic fracture fixation techniques
Comminuted fractures are bridge plated
Simple fractures are anatomically reduced and compression plated. Simple patterns are at greatest risk for excessive stripping
Extensive soft tissue stripping during cable application Cables should be passed through muscle rather than circumferentially under muscle
Mismatch between plate contour and bone causes malreduction Fine adjustments to precontoured plates especially in the zone of greater trochanter and distal metaphyseal flare are often required
Locked screws placed after reduction should not alter reduction
Inadequate proximal fragment fixation Standard fixation around the zone of femoral implant with cables can be supplemented with locked screws into trochanteric region
Screws can be placed into cement mantle just distal to stem
Cables are sequentially tightened and retightened akin to tightening lug nuts
Exclusive use of unicortical locked screws in the proximal fragment provides poor rotational control and should be avoided
Femoral stem is unexpectedly found to be loose Even when stems appear radiographically stable, revision of a loose stem should be considered a contingency
X
When spanning the entire length of the femur with a lateral plate, it is difficult to contour these thick plates to accommodate for both the trochanteric and distal femoral flares. However, when the reduction is obtained prior to plate application, this contour is critical if nonlocked screws or cables are going to be applied. A mismatch between plate contour and bone contour can be accommodated with the placement of locked screws. 
One of the challenges for ORIF of periprosthetic femoral shaft fractures is obtaining adequate fixation in the proximal fragment around the zone of the hip stem. Cables are typically supplemented with screws into the trochanteric region or with unicortical locked screws in the zone of the stem. Relying on unicortical locked screws without cables should be avoided as these constructs have inadequate rotational control. 
Unexpectedly finding a loose femoral stem can be avoided with a careful history and careful observation of prefracture and postfracture radiographs. Even when a careful preoperative evaluation indicates that the stem is stable, intraoperative evaluation of the stem should be performed for confirmation. Access to the distal aspect of the stem is via the fracture. Some authors have advocated performing a hip arthrotomy in all cases to confirm stem stability. 

Revision Arthroplasty of Periprosthetic Femur Fractures

Preoperative Planning for Revision Arthroplasty of Periprosthetic Femoral Fractures

When planning for revision arthroplasty, adequate preoperative imaging is essential for preoperative planning (Table 23-12). These images should be used to determine the type and extent of implants needed. Even for femoral fractures, the status and type of socket is important. Even if the socket appears well fixed, it is reasonable to have revision options. For liners, modular liners can be very helpful and time saving. Increasing head size and using lipped, lateralized, or constrained liners are often necessary for hip stability. The size of the socket will determine the liners that can be cemented in if this becomes necessary. Bone defects on the femur or socket evident on x-rays will dictate the need for particulate bone graft or structural bone graft such as cortical strut. Cerclage wires should always be available. Trochanteric fixation options including plates, heavy suture, or wires should be available based on the particular radiographic features. The extent of the fracture and the quality of the bone can be determined on x-ray and this will guide the femoral fixation options. A proximal fracture can be solved with many standard nonmodular stems but distal fractures or complex femoral problems often require modular titanium stems, and having bowed options is essential for long-stemmed implants or very bowed femurs. Some very osteoporotic femurs require very wide stems that are best prepared using hand reamers. Fluoroscopy will be useful for reaming close to a bowed femur. If there is only a very short segment available for fixation before the distal femoral metaphyseal flare, there should be options for a megaprosthesis or allograft–prosthesis composite. If the femur has a very severe bow or varus remodeling, preoperatively, there should be plans for a femoral osteotomy and this would require fixation options (often cerclage wires) and may require cortical strut grafts or plates for supplemental fixation. Many cases require a “plan A” and a “plan B” and the implants for either plan should be arranged preoperatively. Imaging should be readily accessible in the operating suite and templating will allow implant suppliers to provide outlier sizes and nonroutine bone graft. 
 
Table 23-12
Revision Hip Arthroplasty for Periprosthetic Femur Fractures
Preoperative Planning Checklist
  •  
    OR table: Radiolucent table with pelvic positioner that allows fluoroscopy
  •  
    Intraoperative fluoroscopy or plain radiograph capability
  •  
    Good quality and templated x-rays
  •  
    Cell saver and blood products
  •  
    Equipment: Bone graft based on preoperative plan, cerclage wires, large fragment plate, and screw system
  •  
    Implants: Revision acetabular and femoral options as outlined above
X

Positioning for Revision Arthroplasty of Periprosthetic Femoral Fractures

The patient position for ORIF of periprosthetic femoral shaft fractures can be either lateral decubitus or supine and must take into consideration positioning requirements of the preferred approach for fracture fixation (usually the lateral approach) and revision arthroplasty if needed. Vancouver type A fractures are typically treated in the lateral decubitus position to facilitate access to the trochanteric region. The OR table must provide for unencumbered fluoroscopy of the entire femur and hip. In general, lateral positioning is preferred as it provides greater ease for the surgeon. In this position, the soft tissues require less retraction and the surgeons’ view is in the preferred vertical plane rather than the horizontal as compared to operating with the patient supine. Positioning aids used to hold the patient lateral must be radiolucent. Typically, beanbags meet this requirement but peg boards do not. The torso and contralateral pelvis should be stabilized and the ipsilateral hip should be free to flex, extend, abduct, and adduct with minimal interference from the positioning aids. The contralateral hip is flexed to minimize interference with lateral fluoroscopic radiographs. Consistent with lateral positioning for any procedure, an axillary roll is used and the down leg is padded to protect the bony prominences, namely the proximal fibular head and lateral malleolus, and protect the peroneal nerve from compression. The torso and down leg are secured to the OR table in standard fashion. When supine positioning is utilized, the ipsilateral limb is brought to the edge of the OR table and a small bump can be placed beneath the ipsilateral hip to place the limb in neutral rotation at rest. 
Standard surgical prep and draping is performed with care to allow access to the limb from the top of the ilium to at least the midcalf. The affected extremity is draped free and typically a tourniquet is not used. However, for distal exposure and reduction of Vancouver type C fractures, a sterile tourniquet may be utilized and then removed. 
Fluoroscopy is generally required. The C-arm is positioned on the opposite side from the operating surgeon toward the patient’s front when positioned lateral, and on the contralateral side when supine. The monitor is placed on the contralateral side near the table foot to allow easy visualization by the primary surgeon. The contralateral lower extremity has the propensity to block lateral views, whether lateral or supine positioning is used. This is one reason why, when positioned lateral, hip motion should be unencumbered. By flexing or extending the hip, overlap of the contralateral leg can be avoided. With the patient supine, 10 to 20 degrees of external rotation of the limb and a matching amount of C-arm rotation allows a lateral x-ray without overlap of the contralateral leg. 
For revision hip arthroplasty, the patient should be positioned to allow the most extensile and flexible approaches to the pelvis, hip joint, and femur. Typically, the lateral position with the operative side up and a suitable pelvic positioner, one that allows for unencumbered fluoroscopic radiographs, is the most versatile option. Supine positions allow easier access by fluoroscopy but little extensile options. With the lateral position, orthogonal plain radiographic views can be obtained easily though fluoroscopy is challenging. 

Surgical Approach(es) for Revision Arthroplasty of Periprosthetic Femoral Fractures

For revision arthroplasty, the most extensile approach to the femur, hip, and pelvis is the posterior-lateral approach. This approach can be extended down the femur, as described previously in this chapter for ORIF, to the knee as needed. The muscular (and vascular) attachments to the femur and fracture fragments can be preserved. 

Revision Arthroplasty Technique of Periprosthetic Femoral Fractures

The specific revision strategy chosen depends on the quality of the remaining bone stock, the diameter of the femoral canal distal to the fracture, and patient factors such as age and baseline functional status (Table 23-13). Through the fracture site, cement and cement restrictors can be removed. If necessary, an extended trochanteric osteotomy of the proximal fracture fragment can allow excellent access for stem removal and direct visualization of the distal canal to allow accurate reaming.158,262 The acetabular component is typically exposed more easily after the femoral component is removed. The liner is removed if modular and the acetabular component is manually tested for stability. If it is loose, acetabular revision is performed. If it is well fixed, the liner is typically exchanged, and the head size increased, if possible, to allow improved hip stability. 
Table 23-13
Revision Arthroplasty for Periprosthetic Femoral Shaft Fractures
Surgical Steps
  •  
    Appropriate patient position with a suitable pelvic positioner that provides excellent stability to limb manipulation but does not encroach on the surgical field or block limb flexion
  •  
    Drape and prep widely (up to the iliac wing and below the knee)
  •  
    Allow free movement of the operative extremity in all planes. Allow access to the contralateral limb for referencing femoral length and knee position
  •  
    During exposure, recreate plane between gluteus maximus and abductors
  •  
    Maintain abductor–greater trochanter–vastus lateralis sleeve, especially if the greater trochanter is mobile
  •  
    Extend incision along femur distally. Deep to the fascia, follow intermuscular plane posterior to vastus lateralis proximally and along intermuscular septum distally. Identify and coagulate perforator vessels. The sciatic nerve can be palpated and can be detensioned by releasing the gluteus maximus sling off the linea aspera. Preserve soft tissue attachments to femur as much as possible. Dissect down to the intact femoral shaft
  •  
    The femoral component can be removed through the fracture if feasible or a coronal split of the proximal involved femur can be utilized if it will not be used for fixation later
  •  
    Acetabular work is easier after the femoral component is removed. If the acetabular component is well fixed, a modular exchange of the polyethylene can be done, increasing the head size if possible. Cementing a liner is a good option if modular options are not available
  •  
    The distal intact femur is prepared for the appropriate stem. A cerclage wire is recommended at the mouth of the distal femoral bone to prevent fracture here. This is especially important at the distal diaphysis
  •  
    The trial femur is assembled. Length can be referenced via the other limb and tension of the abductor/vastus sleeve if the usual soft tissue tension measures are absent. Stability of the hip joint is an important part of the evaluation with the trials. Special attention should be made to anteversion of the trials so this can be recreated with the implant. Combined anteversion can be optimized through the stem if the existing socket does not have adequate anteversion
  •  
    If there is adequate distal fixation, soft tissue tension, and hip stability, the final stem can be assembled and inserted in a meticulous manner to avoid distal fracture and to recreate the anteversion and length of the trials
  •  
    Closure is done in a standard manner with attention to hemostasis and repair of the posterior pseudocapsule or abductor tendon depending on the approach. If the trochanter is mobile, this can be repaired with a trochanteric plate, cerclage wires, or heavy suture depending on the specific procedure.
X
Often, the greater trochanter with its abductor attachments is compromised by the fracture or surgical treatment. In addition to repairing it as described previously, maintenance of the abductor/vastus lateralis soft tissue sleeve attachments is highly recommended as this will prevent trochanteric escape and proximal migration from the pull of the abductors. In many cases, stable trochanteric bony union is not feasible or likely and maintaining this soft tissue sleeve will help to achieve a stable fibrous union. 
Several strategies can be used for the femur, but all rely on obtaining secure distal fixation. Only rarely is cemented long stem revision considered. This can be useful in very osteopenic bone with a capacious canal129 or in elderly patients with limited life expectancy and who are unable to undergo prolonged protected weight bearing or extensive procedures.48 If the fracture is anatomically reduced and fixed with cerclage cables and if the cement not vigorously pressurized, cement extravasation will not typically occur. After cementation, intraoperative radiographs are recommended to determine if any problematic cement extravasation has occurred. Cement extrusion into the fracture site will impair fracture healing. It should be emphasized that cemented reconstructions are rarely useful in the setting of periprosthetic fractures. The most effective strategies include noncemented distal fixation techniques. 
Preoperative radiographic findings can help guide the selection of the appropriate uncemented reconstruction. These include the endosteal diameter and morphology of the distal fragment. If the distal fragment demonstrates parallel endosteal cortices with 5 cm or more of tubular diaphysis (usually with a diameter of less than 18 mm), then an extensively coated uncemented long stem prosthesis with or without lateral plate augmentation is appropriate (Fig. 23-7B). The distal canal is reamed and a trial stem is potted into the distal fragment. The proximal fragments can then be reduced using the trial implant as a template. Cerclage cables are applied and a trial reduction is performed. Once leg length and stability are acceptable, the trial is removed and the femoral component is impacted. The cerclage cables are then retensioned, crimped, and cut. The appropriate femoral head length is selected and the reconstruction completed. These types of stems have demonstrated excellent long-term survivorship in the revision setting and for periprosthetic fracture situations.140,160,195,206 Union occurs reliably and functional outcome is, as expected for complex revision arthroplasty, modest. At a mean follow-up of 10.8 years, 17 of 22 patients treated with an extensively porous-coated implant had a satisfactory functional result with delayed union occurring in only one.206 Concomitant acetabular revision was required in 19 patients. Another similarly treated group of 24 patients had an average Harris Hip Score of 69 with 91% of fractures uniting uneventfully.195 
If the distal diaphysis demonstrates divergent endosteal morphology, or large diameters (typically over 18 mm), fluted titanium-tapered modular stems can be used effectively. These stems are commercially available in diameters up to 30 mm and can be useful in capacious canals. Reaming under fluoroscopic control and “by hand,” especially in osteopenic bone, can help to avoid anterior femoral cortical perforation. When axial stability is obtained by diaphyseal reaming, the implant is impacted into place. It is wise to place a prophylactic cable at the mouth of the distal fragment prior to stem impaction. The proximal bodies of the modular implants are then chosen to restore appropriate leg length, offset, and hip stability. In addition, these stems allow flexibility with femoral anteversion which can be useful in enhancing hip stability. After trialing, the components are assembled and the hip reduced. The proximal fragments are then reduced and cerclaged around the body of the implant (Fig. 23-13). The author finds this strategy effective for Vancouver type B2 and even some B3 fractures; however, concerns remain about the durability of the modular junction of such stems without proximal bony support. Modular, tapered titanium stems have gained popularity in any revision setting but the issue of modular junction failures has not clearly been solved. There have been numerous clinical series in the last few years verifying the utility and clinical success of noncemented fixation especially with modular diaphyseal engaging titanium stem.77,200,226 
Figure 23-13
A highly comminuted fracture about a loose femoral stem (Vancouver Type B2) (A) is managed with a long stem modular prosthesis (B).
(Courtesy of Hari Parvataneni, MD.)
(Courtesy of Hari Parvataneni, MD.)
View Original | Slide (.ppt)
X
Rarely, the proximal bone is so deficient that either a modular proximal femoral replacement (so called “tumor prosthesis”) (Fig. 23-14),137,303 proximal femoral allograft,133,178 or impaction grafting with plate fixation278,280 is appropriate. The former two methods are typically used in very osteopenic bone; therefore, cemented distal fixation is recommended. Preserving a sleeve of remaining proximal bone, albeit deficient, provides some soft tissue attachment and assists in maintaining a stable hip. In addition, maintaining the abductor/vastus sleeve attached to the greater trochanter bone fragment helps to prevent trochanteric escape (Fig. 23-14C). A coronal split (Wagner type) of the proximal bone can facilitate stem removal. The new implant is cemented into the distal fragment, and then the proximal sleeve of remaining bone and soft tissue can be cerclaged around the body of the proximal femoral replacing prosthesis or the proximal femoral allograft/revision stem composite (Fig. 23-15) with cable or heavy braided suture. Results of these extreme revision scenarios are not as good as seen with the less complex revisions associated with type B1 fractures. Patients should be counseled that neither bone healing nor function are predictably good, but that both can be satisfactory. Twenty-three of 24 patients treated with such an allograft/implant composite for Vancouver type B3 fractures were able to walk but 15 required a walker.133,178 Osseous union of the allograft to host femur occurred in 80% and union of the greater trochanter occurred in 68%. At a mean follow-up of 5.1 years, 16% had required a repeat revision. In a series of 21 similar fractures treated with a proximal femoral replacement and followed for 3.2 years, all but one was able to walk.137 Despite a relatively high complication rate (two wound drainage, two dislocations, one refracture distal to the femoral stem, one acetabular cage failure) the authors concluded this was a viable option for patients with a severe problem. A more recent review of 20 patients undergoing megaprosthesis reconstruction for periprosthetic fracture confirms acceptable results in terms of function and satisfaction at a mean of 48 months but with a high complication rate (six major complications in 20 patients).182 When impaction grafting technique is chosen, better results have been demonstrated with the use of a long-stem femoral component that bypasses the fracture then with a short stem.280 It is important to note that if the abductors are deficient then any of these constructs should include a constrained acetabular liner to minimize the risk of postoperative dislocation. If the acetabular component is of sufficient diameter and a compatible constrained liner is not available, some surgeons have recommended cementing a constrained liner into a well-fixed acetabular component. Good containment of the locked liner by the acetabular component is required, and cup position should be acceptable. Contouring the backside of the liner to be cemented is recommended (if it is smooth) to allow cement interdigitation. 
Figure 23-14
A fracture associated with a loose prosthesis and bone loss from osteolysis (Vancouver Type B3) (A) is treated with a proximal femoral replacement.
 
An intraoperative photograph (B) shows sizing of the stem and postoperative radiographs show reattachment of the abductor/vastus lateralis sleeve (C). (Courtesy of Hari Parvataneni, MD).
An intraoperative photograph (B) shows sizing of the stem and postoperative radiographs show reattachment of the abductor/vastus lateralis sleeve (C). (Courtesy of Hari Parvataneni, MD).
View Original | Slide (.ppt)
Figure 23-14
A fracture associated with a loose prosthesis and bone loss from osteolysis (Vancouver Type B3) (A) is treated with a proximal femoral replacement.
An intraoperative photograph (B) shows sizing of the stem and postoperative radiographs show reattachment of the abductor/vastus lateralis sleeve (C). (Courtesy of Hari Parvataneni, MD).
An intraoperative photograph (B) shows sizing of the stem and postoperative radiographs show reattachment of the abductor/vastus lateralis sleeve (C). (Courtesy of Hari Parvataneni, MD).
View Original | Slide (.ppt)
X
Figure 23-15
Proximal femoral allograft-revision stem composite for treatment of Vancouver Type B3 periprosthetic femur fractures.
 
A: The allograft–prosthesis composite is inserted into the native host distal femoral segment. B: Any remaining proximal sleeve of split host bone with soft tissue attachments is secured to the allograft and across the allograft-host junction. C: The greater trochanter is separately attached to the allograft.
A: The allograft–prosthesis composite is inserted into the native host distal femoral segment. B: Any remaining proximal sleeve of split host bone with soft tissue attachments is secured to the allograft and across the allograft-host junction. C: The greater trochanter is separately attached to the allograft.
View Original | Slide (.ppt)
Figure 23-15
Proximal femoral allograft-revision stem composite for treatment of Vancouver Type B3 periprosthetic femur fractures.
A: The allograft–prosthesis composite is inserted into the native host distal femoral segment. B: Any remaining proximal sleeve of split host bone with soft tissue attachments is secured to the allograft and across the allograft-host junction. C: The greater trochanter is separately attached to the allograft.
A: The allograft–prosthesis composite is inserted into the native host distal femoral segment. B: Any remaining proximal sleeve of split host bone with soft tissue attachments is secured to the allograft and across the allograft-host junction. C: The greater trochanter is separately attached to the allograft.
View Original | Slide (.ppt)
X
When postoperative fractures occur around loose implants, revision strategies should rely on diaphyseal, not proximal fixation. The diameter, geometry, and bone quality of the diaphyseal bone will determine whether an extensively coated cylindrical stem or a tapered modular stem is appropriate. Extensively coated cylindrical stems are appropriate in smaller canals (<18 mm), simple fracture patterns, and in situations where 5 cm of parallel diaphyseal endosteum is available for fixation. This situation is rare, therefore we generally prefer to osteotomize the proximal femur, utilizing existing fracture lines, if possible, for direct access to the diaphysis, and then obtain distal fixation with a tapered modular stem. Modular trials are used to restore leg length and hip stability. After the assembly of the implant, the proximal fragments are stabilized with cerclage, typically utilizing cables, using the intramedullary stem as an “endoskeleton.” Rarely, the proximal bone is so deficient that proximal femoral replacement with a modular megaprosthesis is necessary. An effort should be made to preserve the proximal femoral muscular attachments. We prefer to “wrap” any residual bony fragments around the megaprosthesis with cerclage in an attempt to improve construct stability. Obviously, if there are any acetabular component issues, they can be addressed simultaneously, either with modular liner exchange or cup revision as indicated. 

Postoperative Care for Revision Arthroplasty of Periprosthetic Femoral Fractures

Weight-bearing status will depend on the quality of the bone and fixation. Typically, protected weight bearing is recommended for 6 weeks to 3 months to allow early bony incorporation of the implants. Special precautions should be emphasized for dislocation which is much more likely with complex revision surgery and if the greater trochanter is repaired. Trochanteric precautions (protected weight bearing and minimal active abduction) may be indicated if there is a high chance of trochanteric escape. Close attention should be given to wound issues or persistent drainage. Regularly scheduled radiographs will guide activity advancement and need for further intervention. 

Potential Pitfalls and Preventative Measures for Revision Arthroplasty of Periprosthetic Femoral Fractures

Revision hip arthroplasty in the setting of periprosthetic femur fracture requires wide surgical exposure (Table 23-14). Wide draping as well as care that positioners do not inhibit extensile exposure should be taken. A wide array if revision implants may be required and should be confirmed as being available, including multiple lengths and sizes. Occasionally, a worn or cracked acetabular liner or a loose acetabular component is unexpectedly encountered. Therefore, implants and equipment for acetabular revision should also be confirmed as available. 
Table 23-14
Revision Arthroplasty for Periprosthetic Femoral Shaft Fractures
Potential Pitfalls and Preventions
Pitfalls Preventions
Inadequate surgical field Drape and prep widely (above iliac crest to below knee)
Ensure pelvic positioner does not encroach on the field anteriorly or posteriorly
Use an extensile incision that allows access to the entire femur and much of the pelvis
Limited implant options Preoperative planning for selection of acetabular socket, liner, femoral fixation, and bone graft options
Pay special attention to large femurs requiring outlier sizes, bowed femurs, small sockets that will not allow many options for hip stability, constrained liners if the abductors are dysfunctional, trochanteric fixation options, and “backup implants” such as a megaprosthesis
Propagation of the fracture distally Meticulous bone preparation with trialing prior to stem insertion. If the stem is not advancing, reprepare the femur. Cerclage wire (s) at the mouth of the diaphysis just distal to the fracture
For bowed stems, flexible reamers are needed and often require variable over reaming
Inadequate hip stability Pay attention to combined anteversion, status of abductors, and soft tissue tension. Increase head size if possible. Have lipped and lateralized liners available. Constrained liners must be available if there are deficient abductors or instability that cannot be solved with other options
X
Implantation of a long femoral stem across a femoral shaft fracture can generate substantial stress on the bone. This establishes a risk of fracture propagation. Preparation of the canal with flexible reamers can accommodate for the normal femoral bow. With meticulous preparation of the canal, careful selection of the appropriate size prosthesis, and with meticulous insertion technique, iatrogenic fracture risk can be minimized. As with any revision hip arthroplasty, stability of the hip joint is a potential issue. Proper anteversion, adequate soft tissue tension, larger head size, and an elevated liner each can improve stability. A constrained liner should be available if hip stability cannot be accomplished with standard means. 

Outcomes of Periprosthetic Femur Fractures

Outcomes of Vancouver A Periprosthetic Femur Fractures

Among Vancouver types A, B, and C periprosthetic fractures, only type A fractures are treated nonoperatively with any regularity. In a series of 30 Vancouver type A fractures treated nonoperatively, 90% had displacement of 2.5 cm or less.221 A combination of superior and medial displacement was typically observed and only three patients (10%) had a secondary increase in displacement. Functional outcomes were marginal with 12 patients (40%) experiencing pain or limp. However, only three had symptoms persistent and severe enough to warrant operative repair. Two of these three experienced improvement. No dislocations occurred in this series; however, in another small series of six patients treated nonoperatively for a Vancouver type A fracture, two had subsequent dislocation within 2 months.112 Minimally displaced postoperative fractures occurring through osteolytic lesions 4 to 11 years after THA treated nonoperatively yielded union in 15 of 17 patients.120 At a mean follow-up of 3 years after fracture 16 had revision THA, the majority for excessive wear and component loosening. 
There is very little in the way of published modern series of acute Vancouver type AG fractures to guide treatment and establish expected outcomes. Much of the available information includes or is exclusively related to treatment of greater trochanteric osteotomies or nonunions.96,163,165,166 In a recent series of 31 cases of claw plate fixation of the greater trochanter, only eight were for acute fracture.166 Results for these patients were not distinguished. Overall, union occurred in 28 of 31 patients with three having fibrous union of the trochanter. Other complications included painful bursitis requiring plate removal in three patients and deep infection in one. In the setting of greater trochanteric nonunion, adjunctive vertically oriented wires have resulted in better osseous contact and union.290 

Outcomes of Internal Fixation of Vancouver Types B and C Periprosthetic Femur Fractures

The results of traditional nonlocked plate and screw fixation for periprosthetic femoral shaft fractures using now outdated direct reduction techniques have been varied.30,53,76,87,186,190,192,268,276,285,308,312 Failure of traditional cable-plate constructs with cable fixation in zone of intramedullary implant and nonlocked screws distally is likely related, at least in part, to older direct reduction techniques and not necessarily to an inappropriate construct (Fig. 23-16). Soft tissue stripping associated with direct reduction can delay healing which eventually manifests as implant failure. The addition of strut grafts 90 degrees to a lateral plate offers increased immediate as well as prolonged construct stability (Fig. 23-17) and has been associated with good results.98,286 In a report on 40 patients, Haddad et al.98 concluded that cortical allografts should be used routinely to augment fixation and healing of periprosthetic femoral fracture around well-fixed implants. Treatment methods varied in this study and included cortical onlay strut allograft alone, a plate and one cortical strut, or a plate and two struts. The nonstandardized use of other adjuvant bone grafting materials in this study further increased the heterogeneity of the treatment methods: eight patients received autograft, 29 received morselized allograft, and 15 received demineralized bone matrix. Based on 100% healing, it is logical to conclude that the use of strut allografts plus adjuvant bone graft and/or lateral plate fixation can achieve good results. However, it may be overstated to conclude that allograft is a requirement for treatment of Vancouver B1 fractures. 
Figure 23-16
High failure rates have been associated with lateral plate fixation when older, direct, nonbiologically friendly reduction techniques are utilized (A, B).
Rockwood-ch023-image016.png
View Original | Slide (.ppt)
X
Figure 23-17
An intraoperative clinical photograph showing lateral plate fixation augmented with an anterior femoral strut allograft.
Rockwood-ch023-image017.png
View Original | Slide (.ppt)
X
Newer biologic plating techniques that maximally preserve the soft tissue attachments about a fracture have been shown to be successful without adjuvant bone grafting for fractures in other anatomic areas that traditionally were treated with adjuvant bone grafts. Abhaykumar and Elliott2 and Ricci et al.227 were among the first to apply biologic plating techniques to periprosthetic femoral shaft fractures. Neither indirect fracture reduction and a single, laterally applied, plate without the use of structural allograft nor any other substitute was uniformly utilized in the series of Ricci et al.227 Union occurred after the index procedure in all of the 41 patients who lived beyond the perioperative period. The average time required for healing was relatively short, 11 weeks, and was very homogenous with the standard deviation being only ±4 weeks. All patients healed in satisfactory alignment (less than 5 degrees of malalignment). Although minor implant-related complications such as cable fracture occurred in three patients, this did not appear to complicate the healing process. Each of these three fractures healed at between 10 and 12 weeks in satisfactory alignment and without the need for further operation. The consistent healing was attributed to care in preserving the soft tissue envelope around the fracture. Xue et al.300 and Anakwe et al.6 had very similar results in smaller series, 12 and 11 cases, respectively treated in nearly the identical manner: single lateral plate, screw fixation distally, screw and cerclage fixation proximally, and without the use of adjuvant bone grafts. All patients from both studies healed after the index procedure, with one patient having a delayed union and one with proximal screw loosening in Xue’s series. These results compare favorably to treatment of similar fractures using cortical onlay grafts alone,38,39,98,294 where nonunion requiring revision surgery has been reported in 8% to 10% of cases38,39,294 and where angular malunion has been reported to occur in 5% to 10% of cases.38,98 The reason for the higher malunion rate seen when allograft strut fixation is used alone may be because these struts cannot be bent or contoured as can plates. Fracture alignment, therefore, cannot be adjusted with struts as precisely as with the use of plates. Good clinical results of isolated locked compression plating technique, without the use of cables, has been reported in small series of patients (10 to 13), all who accomplished union after the index procedure.28,66 It is important to recognize that in these series all patients had bicortical fixation in the proximal fragment including bicortical locking screws anterior or posterior to the prosthesis, bicortical fixation into the lesser trochanter, or bicortical fixation into the greater trochanter, or some combination of these methods. Constructs relying on unicortical fixation, without any bicortical fixation, have poor rotational control and are not recommended. Other recent series of ORIF for Vancouver types B and C fractures utilizing plates have not shown universally good results. Plating with the less invasive stabilization system (LISS) for 19 patients yielded two delayed unions and four implant-related complications each requiring revision ORIF.196 Another small study of 10 patients treated with ORIF reported surgery-related complication in 62.5% of cases.151 
A host of biomechanical studies exist to define the characteristics of various plate constructs used for Vancouver type B fractures.29,59,60,84,269,306 The so-called Ogden-type construct (Fig. 23-18), cables proximally and standard nonlocked screws distally, is the typical control construct in these biomechanical studies. Prior to the advent of locking plates, cortical allograft struts either in place of or in addition to the Ogden concept were the focus of testing.60,59 More recently, the use of proximal unicortical locking screws either in lieu of or in addition to cables has been investigated.84,269,306 In each of these studies, the stiffness of various experimental constructs was greater than the Ogden construct but fatigue characteristics were not investigated in the majority of studies, limiting the clinical applicability of these investigations.59,60,84,306 The recent clinical series utilizing modern biologic plating techniques have shown good results with slight modification of the Ogden construct. Addition of locked screws in the proximal segment to augment (but not replace) cables and bicortical locked screws in the distal segment to augment nonlocked screws in the presence of osteoporotic bone has been reported with good results (Figs 23-18 and 23-19).2,227 Unicortical locked screws alone, without cables or bicortical screws around the prosthesis, have not been shown to provide adequate fixation for these fractures. This is primarily because of the poor rotational stability of such short unicortical screws. Therefore, locked screws should be used as an adjunct to, but not as a substitute for, cable fixation in the zone of the hip prosthesis. A biomechanical study attempting to evaluate the effect of unicortical and bicortical screws on the cement mantle provided mixed results: unicortical screws induced few cracks but had less holding power than bicortical screws.128 Any clinical long-term detrimental effect of unicortical or bicortical screws inserted into a cement mantle remains unknown. 
Figure 23-18
AP view of the traditional Ogden type construct with cable fixation proximally and nonlocked screw fixation distally.
Rockwood-ch023-image018.png
View Original | Slide (.ppt)
X
Figure 23-19
Fixation of midshaft femur fractures with a bowed plate helps preserve anatomic alignment in the sagittal plane.
Rockwood-ch023-image019.png
View Original | Slide (.ppt)
X
The specific type of plate utilized for fixation of periprosthetic femoral shaft fractures is probably less important than the technique utilized for its implantation. A number of designs that employ various mechanisms for attachment of cables through or around the plate are available. However, good results have been achieved with standard plates.2,98,227,228 A plate that is bowed in the sagittal plane to match the anterior femoral bow makes sense to assist in obtaining an anatomic reduction in this plane (Fig. 23-19). 
The subsidence of stems after wiring of minimally displaced intraoperative fractures was evaluated in a series of 38 patients all with the same short-stemmed prosthesis and compared to a control group without a fracture.307 There was no significant migration at an average 5.7 years of the stems in the study group compared to the control group. Also, the frequency of radiolucent lines was not different between the study and control groups. 

Outcomes of Revision Arthroplasty for Vancouver Types B and C Periprosthetic Femur Fractures

The overall functional outcome based on the Oxford Hip Score (OHS) for revision arthroplasty in the setting of periprosthetic fracture has been found, in a large comparative analysis (n = 232 revisions for fracture), to be worse than when revision is for aseptic loosening.302 Further, this study demonstrated an eightfold higher mortality rate (7.3%) seen in the periprosthetic fracture patients. These data are consistent with the high mortality rates (11%) seen in patients treated with ORIF for periprosthetic femur fractures269 and together paint a sobering picture of the seriousness of these injuries. Langenhan et al.,149 because of high mortality rates after ORIF, altered their treatment protocol in 2001 and began performing stem replacement with a distally locked modular prosthesis nail for the majority of periprosthetic femur fractures, Vancouver B and C, regardless of stem stability. This strategy permitted immediate full weight bearing and therefore improved mobility compared to patients treated with ORIF and protected weight bearing. The authors attribute the decrease in mortality to the improved mobility seen in their group of 29 patients who underwent revision arthroplasty (10 died at final follow-up and three died early) compared to the 23 patients treated with ORIF (21 died at final follow-up and seven died early). Subgroup analysis of patients with Vancouver B1 fractures showed no significant difference in 6-month mortality between groups, but this analysis was likely underpowered. Another retrospective study comparing ORIF to revision arthroplasty for Vancouver B and C fractures failed to show differences in systemic complications between groups.151 This study did, however, reveal more surgery-related complications in the ORIF group (62.5% vs. 18.8%). 
Results after revision THA associated with periprosthetic femur fractures appear to be inferior to those for revision for aseptic loosening. Data from the New Zealand National Registry showed functional outcomes based on the Oxford Hip Score (OHS) to be worse following revision THA for periprosthetic fracture than in reference patients (mean OHS: 29 vs. 24).302 Also, there was a higher likelihood of revision (7.3% vs. 2.6%) and higher 6-month mortality (7.3% vs. 0.9%). Reoperation in 7 of 25 patients with Vancouver B2 and B3 fractures treated with revision alone or revision + ORIF was reported.312 

Outcomes of Fractures About Femoral Resurfacing Prostheses

Cossey et al.50 reported on seven patients with nondisplaced femoral neck fractures associated with the Birmingham hip resurfacing procedure that were treated nonoperatively. All fractures occurred within 4 months of surgery and all were treated with non–weight-bearing. At a minimum of 16 months post fracture, all fractures were united and all patients were without impaired function. One patient was noted to have marked femoral neck narrowing that appeared asymptomatic. Jacobs et al.123 described 13 patients treated nonoperatively for femoral neck fracture after hip resurfacing. All healed with nonoperative management; however, four healed in varus. No follow-up beyond fracture healing was presented, so the consequence of varus union in this population remains unknown. Nonoperative management for nondisplaced fractures and revision to THA for displaced fractures was advocated. 

Author’s Preferred Treatment of Periprosthetic Femur Fractures about Hip Arthroplasty Stems

 
 

We find the Vancouver classification very useful in determining treatment for periprosthetic femoral shaft fractures (Fig. 23-20). Nondisplaced Vancouver A fractures are generally treated nonoperatively with protected weight bearing based on comfort unless the fracture is noticed intraoperatively. In such cases, we have a lower threshold for cable or claw plate fixation. Widely displaced Vancouver A fractures are generally treated with ORIF with a claw plate and cables.

 
Figure 23-20
Algorithm depicting the author’s preferred method of treatment for periprosthetic femur fractures about hip arthroplasty stems.
Rockwood-ch023-image020.png
View Original | Slide (.ppt)
X
 

Vancouver B1 fractures are usually treated with ORIF via a lateral approach. These fractures are typically simple spiral patterns and we prefer to use cables to help obtain and maintain a provisional reduction. Fixation is with a lateral locked plate which is secured proximately with cables and then with locked screws into the trochanteric region. Distal fixation is with a combination of nonlocked and locked screws depending upon the bone quality. Lag screws are placed across the fracture through the plate whenever feasible. We prefer to protect the entire length of the femur and therefore select a plate that extends at least to the distal metaphyseal flare and we usually utilize a distal femoral locking plate. Comminuted fractures are treated similarly except a bridge plating technique is utilized. We neither generally utilize any bone grafts for Vancouver B1 fractures nor do we perform revision arthroplasty for well-fixed stems.

 

By definition, Vancouver B2 fractures have a loose stem and therefore our treatment incorporates revision of the femoral component. However, in select cases when the patient’s functional demands are severely limited, and when the patient had no preoperative symptoms associated with the loose prosthesis, we may forgo revision arthroplasty especially if the patient has substantial cardiopulmonary comorbid disease that increases the risk of intraoperative or postoperative medical complications. In most cases, we perform revision arthroplasty with bowed noncemented stems across the fracture. We also generally supplements revision arthroplasty with a long lateral plate that protects the entire femur from future fracture. If there are bone defects, these are managed with structural allograft in addition to the lateral plate.

 

Vancouver B3 fractures present substantial technical challenges. We highly recommend these fractures be placed in the hands of a surgeon that is well versed with revision hip arthroplasty technique as well as proximal femoral replacement technique. As with other types of periprosthetic femur fractures, we typically protect the entire femur with a lateral plate after revision arthroplasty.

 

We treat Vancouver C fractures according to the techniques outlined for plate and screw treatment of distal femur fractures. Typically, a lateral lock plate is utilized. We are careful to use plates long enough to overlap the femoral stem such that two cables can be placed that are spaced apart by 3 to 4 cm.

Periprosthetic Distal Femur Fractures about Total Knee Arthroplasty

Incidence, Risk Factors, Prevention, and Mortality for Periprosthetic Distal Femur Fractures

Approximately 300,000 primary knee arthroplasties are performed annually in the United States, and this number continues to increase. It is estimated that 0.3% to 2.5% of patients will sustain a periprosthetic fracture as a complication of primary TKA.11,56,184,190 The prevalence of these fractures is substantially higher (1.7% to 38%) after revision TKA.184,209 Patient-specific risk factors such as RA, osteolysis, osteopenic bone, use of steroid medications, frequent falls common in the elderly population, and technique-specific risk factors such as anterior femoral cortical notching have all been implicated as potential causes of periprosthetic fractures. In a large population-based study from Scotland that included 44,511 primary and 3,222 revision TKAs, female gender, age >70, and revision arthroplasty were associated with risk of fracture.184 Although tibia fractures about unicompartmental knee arthroplasty has been identified in a number of reports, fractures about the femur in association with unicompartmental knee arthroplasty has rarely been reported.136 
Intraoperative fracture of the femur during TKA is much less common than femur fracture during THA. It has been reported to occur in 49 cases out of 17,389 primary TKAs.3 Of the 49 fractures identified in this series, 20 were of the medial condyle, 11 of the lateral condyle, 8 were complete supracondylar fractures, 7 involved the medial epicondyle, 2 the lateral epicondyle, and 1 the posterior cortex. The majority of fractures occurred in females and most occurred during exposure, bone preparation, and component trialing. 
Osteopenia, from a multitude of potential causes, is a major contributing factor to periprosthetic fractures in TKA.1,30,53,186 Bone mineral density (BMD) in the distal femur has been shown to decrease between 19% and 44% 1 year after TKA compared to initial values.214 Progressive loss in BMD has been reported at 2 years after surgery, possibly from stress shielding in the anterior distal femur. Such reductions in BMD may be an important determinant of periprosthetic fracture.215 Neurologic disorders have also been implicated as etiologic factors,53,157 but this too may be primarily related to osteopenia from associated disuse or neuroleptic medications. 
Stress fractures in the femur and tibia associated with a sudden increase in activity soon after TKA have been described and may be related to relative disuse osteopenia occurring with extended periods of inactivity prior to TKA.71 In the femur these stress fractures may occur at any location and may present a diagnostic challenge in a patient that complains of sudden onset of pain without antecedent trauma and without signs of infection.51,105,148,157,207,224 Repeat plain radiographs a period of weeks after the onset of symptoms may reveal the previously occult stress fracture or a bone scan may be diagnostic earlier. With an index of suspicion, protected weight bearing is prudent until stress fracture is ruled out. When ruled in, protected weight bearing for approximately 6 weeks followed by gradual advancements is usually a successful treatment plan. 
With or without associated osteopenia, several local factors may further contribute to the occurrence of periprosthetic fractures above TKAs. Fractures through an osteolytic lesion about TKAs are much less common than their occurrence about femoral hip components, but these certainly may occur.213 Anterior femoral notching has been implicated as another risk factor for subsequent periprosthetic supracondylar femur fracture. Biomechanical evaluations, including cadaveric studies and finite element models, implicate anterior notching as a risk factor for periprosthetic fracture.156,304 When loaded in bending, notched femora failed with a short oblique fracture originating at the cortical defect whereas unnotched femora sustained a midshaft fracture. No difference in failure mode was noted with loading in torsion. The force to failure was significantly less for notched femora than unnotched, 18% less in bending and 39% less than torsion. Finite element analysis has also yielded results that indicate notching reduces the fracture threshold.304 Larger notches, sharper notches, and proximity to the prosthesis each lead to increased local stresses. Despite common sense and laboratory investigations indicating notching as a risk factor for periprosthetic supracondylar femur fractures, clinical data remains unconvincing. The lack of statistical association between notching and fracture may be because of underpowered studies and extremely small numbers of observed fractures. Lesh et al.156 reviewed 164 supracondylar periprosthetic femur fractures reported in the literature and noted more than 30% were associated with notching. Many of these patients, however, were noted to have other risk factors for fracture. Three separate large retrospective studies (>200 patients) failed to find an association between notching and fracture.97,234,235 However, with very few fractures (three or less) in each of these cohorts, statistical power is lacking in each to rule out an association between notching and fracture. Other studies, however, suggest notching may predispose to subsequent fracture. Aaron and Scott1 found that 42% of patients with excessive notching suffered fracture, whereas none of those without encroachment of the anterior cortex fractured. A study that included a cohort of patients with supracondylar fractures, but without a denominator indicating how many patients without fracture did and did not have notching, found a large proportion (up to 25%) of fractures associated with notching.155 Further supporting the association of notching and fracture are the findings that the time from index arthroplasty to fracture was 37.5 months in patients with notching compared to 80.3 months in those without and that the distance from the anterior flange of the femoral component to the fracture was significantly shorter in patients with notching (3.6 mm) than in patients without notching (39 mm).155 It has also been postulated that bone remodeling around notched areas may reduce risk of fracture97 and that notching is of minimal concern beyond the early postoperative period.235 However, the rate of periprosthetic distal femur fracture has been shown to increase with the number of years after both primary and revision TKA.184 
Prosthetic designs with a posterior stabilized femoral component that removes bone from the intercondylar region has been noted to increase risk for intraoperative fracture.238 Fracture, typically of the medial femoral condyle, is more likely to occur if the component is not centered between the condyles. A relatively new potential risk factor has been described in a case report of periprosthetic supracondylar femur fractures through a navigation pin hole.162 With the increasing popularity of surgical navigation for TKA, this potential complication should be considered when choosing a location for navigation instruments. Another new technology, saline-cooled bipolar radiofrequency, used on the synovium overlying the femoral condyles for hemostasis has been implicated in periprosthetic femoral condyle fractures after TKA.201 Four such fractures occurred shortly after increasing usage of this technology whereas the senior author had no fractures of this kind in 2,500 prior TKAs. It was hypothesized that thermal damage to the bone caused by saline-cooled bipolar radiofrequency reduced the mechanical integrity and predisposed to fracture. 
It is well established that geriatric patients who sustain hip fractures have high mortality rates at any time point relative to their fracture. The combination of stress associated with fracture and treatment, and the comorbid medical conditions commonly present in this population are attributed to the high mortality rates seen. These conditions are also seen in patients with periprosthetic distal femur fractures. It is therefore not surprising that patients with distal femur fractures were found to have high mortality rates (6% at 30 days, 18% at 6 months, 25% at 1 year) that were similar to hip fracture patients.265 Furthermore, in this study, TKA was found to be an independent risk factor for decreased survival. 

Classification of Periprosthetic Distal Femur Fractures

The Lewis and Rorabeck classification scheme for periprosthetic femur fractures about TKAs accounts for fracture displacement and prosthesis stability (Fig. 23-21).161,237 Type I are stable, essentially nondisplaced, fractures and the bone–prosthesis interface remains intact. Type II fractures are displaced with a well-fixed prosthesis. Type III fractures have a loose or failing prosthesis regardless of the fracture displacement. 
Figure 23-21
Classification scheme for periprosthetic fractures about the femoral component of the knee.
 
Type I fractures are minimally displaced with an intact prosthesis–bone interface; Type II fractures are displaced but maintain an intact bone–prosthesis interface; and Type III fractures may be displaced or nondisplaced, but have a loose femoral component. (Modified from: Lewis PL, Rorabeck CH. Periprosthetic fractures. In: Engh GA, Roabeck CH, eds. Revision Total Knee Arthroplasty. Baltimore, MD: Williams & Wilkins; 1997: 275–295).
Type I fractures are minimally displaced with an intact prosthesis–bone interface; Type II fractures are displaced but maintain an intact bone–prosthesis interface; and Type III fractures may be displaced or nondisplaced, but have a loose femoral component. (Modified from: Lewis PL, Rorabeck CH. Periprosthetic fractures. In: Engh GA, Roabeck CH, eds. Revision Total Knee Arthroplasty. Baltimore, MD: Williams & Wilkins; 1997: 275–295).
View Original | Slide (.ppt)
Figure 23-21
Classification scheme for periprosthetic fractures about the femoral component of the knee.
Type I fractures are minimally displaced with an intact prosthesis–bone interface; Type II fractures are displaced but maintain an intact bone–prosthesis interface; and Type III fractures may be displaced or nondisplaced, but have a loose femoral component. (Modified from: Lewis PL, Rorabeck CH. Periprosthetic fractures. In: Engh GA, Roabeck CH, eds. Revision Total Knee Arthroplasty. Baltimore, MD: Williams & Wilkins; 1997: 275–295).
Type I fractures are minimally displaced with an intact prosthesis–bone interface; Type II fractures are displaced but maintain an intact bone–prosthesis interface; and Type III fractures may be displaced or nondisplaced, but have a loose femoral component. (Modified from: Lewis PL, Rorabeck CH. Periprosthetic fractures. In: Engh GA, Roabeck CH, eds. Revision Total Knee Arthroplasty. Baltimore, MD: Williams & Wilkins; 1997: 275–295).
View Original | Slide (.ppt)
X
This classification does not account for the fracture location relative to the prosthesis, a factor that has the potential to dictate treatment. The classification scheme of Su et al.267 divides fractures into three types according to the fracture location relative to the proximal border of the femoral component: Type I fractures are proximal to the femoral component; type II originate at the proximal end of the component and extend proximally; and type III extend distal to the proximal border of the femoral component (Fig. 23-22). 
Figure 23-22
The Su classification of periprosthetic distal femur fractures accounts for location of the fracture relative to the femoral TKA component.
Rockwood-ch023-image022.png
View Original | Slide (.ppt)
X

Nonoperative Management of Periprosthetic Distal Femur Fractures

Nonoperative treatment of periprosthetic supracondylar femur fractures is reserved for nondisplaced fractures or for displaced fractures where patient-based results of nonoperative treatment would be at least as good as operative treatment. For displaced fractures, nonoperative treatment is indicated for nonambulatory patients or those patients who are not likely to survive surgery because of medical comorbidities. 
Nondisplaced fractures can be treated nonoperatively with skeletal traction, splints, casts, and braces or a combination of these methods. Initial treatment, especially if the limb is substantially swollen, is typically with a long leg splint. Once the soft tissue swelling has subsided and the patient has regained reasonable comfort, a long leg brace, such as a knee immobilizer or an unlocked hinged knee brace can be utilized. As with other nondisplaced fractures treated nonoperatively, it is prudent to monitor for secondary displacement with frequent, usually weekly or biweekly, radiographs. Any secondary displacement noted early in the treatment course (e.g., the first 2 weeks) is a relative indication for operative intervention as such early displacement is typically followed by progressive later displacement. 

Outcomes of Nonoperative Treatment for Periprosthetic Distal Femur Fractures

Related to improvements in operative techniques and implants, the vast majority of these fractures are treated operatively, especially displaced fractures. Accordingly, very little attention has been paid to nonoperative management outcomes of periprosthetic supracondylar femur fractures over the last three decades. Only one case focusing on nonoperative treatment could be identified in the last 25 years.258 The poor results, especially malalignment, associated with nonoperative treatment for displaced supracondylar femur fractures was one of the driving forces toward operative management.30,53,76,87,186,192 For example, in the study of Moran et al.,192 eight of nine displaced fractures treated closed resulted in malunion. 

Principles for Operative Treatment of Periprosthetic Distal Femur Fractures

Most displaced periprosthetic distal femur fractures are treated operatively. Only in special circumstances are such displaced fractures treated nonoperatively. When comorbid medical issues make survival of operative treatment questionable, these risks must be weighed against the likely poor outcome of nonoperative management. Nonambulatory patients can be successfully treated nonoperatively; however, even in this circumstance there are potential benefits to operative management. Internal fixation improves patient comfort, facilitates mobilization, and improves ease of care. 
Operative treatment of patients with supracondylar femur fractures associated with TKA prostheses presents unique challenges. The presence of a TKA prosthesis can complicate operative treatment of these fractures by interfering with or precluding the use of standard fixation methods. A TKA prosthesis with a narrow or closed intracondylar space either limits the diameter for a retrograde nail or completely obviates its use.172 Traditional nonlocked plate fixation is prone to varus collapse.56 Fixed-angle implants such as blade plates or condylar screws have limited applicability for very distal fractures or when associated with a TKA prosthesis that has a deep intracondylar box, but may be used successfully when adequate bone above the femoral prosthesis is available.139 These challenges induce the application of alternative methods. Although varying degrees of success have been reported with such alternative methods including thin-wire external fixation,15 the so-called “nailed cementoplasty,”19 fibular allograft supplementation of plate fixation,145 and upside down use of a proximal femoral nail,219 locked plating has become the treatment method of choice for many surgeons as this device offers many theoretic advantages. The multiple locked distal screws provide both a fixed angle to prevent varus collapse and the ability to address distal fractures264 even when associated with a deep intracondylar box. The provision for locked screw insertion into the diaphyseal fragment theoretically improves fixation in the often associated osteoporotic bone. These devices can also be inserted with relative ease and familiarity. 
The results of locked plate fixation for treatment of periprosthetic supracondylar femur fractures above a TKA have been investigated by numerous authors with the initial enthusiasm being tempered by an inability to obtain consistently high union rates.113,220,228,230,272 Intramedullary nailing represents another viable and efficacious option for these fractures.4,91,113,292 Whereas locked plate fixation is applicable to nearly all periprosthetic supracondylar fractures, regardless of the prosthesis design and even for extreme distal fractures, IMN is reserved for a subset of these fractures. The associated femoral component must accommodate the diameter of the driving end of a retrograde nail, a diameter that may be larger than the diameter of the nail shaft, and sufficient distal bone is required. Published galleries of radiographic profiles and reference lists that include intercondylar dimensions of various prostheses are helpful to avoid unanticipated problems when documentation of the component type is unavailable.270 Distal femoral replacement also has a role in certain subsets of patients with periprosthetic distal femur fractures.142,192,240 This treatment method is gaining in popularity and indications are expanding from primarily those patients with loose TKA prostheses to also include patients with well-fixed and well-functioning prosthesis when the prolonged period of protected weight bearing associated with internal fixation methods is undesirable or impractical. 

ORIF of Periprosthetic Distal Femur Fractures

The vast majority of periprosthetic supracondylar femur fractures about a TKA are in the presence of a stable femoral component. Therefore, ORIF can generally be performed in this scenario. Fractures that are distal to the diaphyseal/metaphyseal junction are treated with ORIF with locked plates, even when fracture extension is extremely distal. We have found that locked plating constructs offer satisfactory fixation distally even in these short segments (Fig. 23-23). The important principle for plate fixation of these fractures is the use of biologically friendly, indirect, fracture reduction techniques. 
Figure 23-23
An extreme distal periprosthetic fracture above a TKA (A, B) treated successfully with a distal lateral femoral locking plate (C, D).
Rockwood-ch023-image023.png
View Original | Slide (.ppt)
X
A unique situation that is becoming more and more common is periprosthetic fracture between a TKA and THA, the so-called interprosthetic fracture.171 These fractures have been found to be in the supracondylar region above the TKA about two times more frequently than in the shaft about the THA stem. Treatment of these interprosthetic fractures should follow the principles of the individual type of fracture encountered and simultaneously protect against future fracture. This situation almost universally lends to plate fixation with a long distal femoral locking plate that spans from the distal femur to overlap with the region of the femoral stem (Fig. 23-24) as described for treatment of Vancouver type C fractures taking into account the issues of distal fixation in the presence of the TKA femoral component discussed in this section. 
Figure 23-24
An interprosthetic fracture located in the distal femur is treated with a long distal lateral femoral locking plate that protects the entire femur by overlapping the hip arthroplasty stem.
Rockwood-ch023-image024.png
View Original | Slide (.ppt)
X

Preoperative Planning for ORIF of Periprosthetic Distal Femur Fractures

The strategy for ORIF of periprosthetic supracondylar femur fractures starts with consideration of the fracture details to determine the fixation method (Table 23-15). A simple fracture pattern amenable to compression plating techniques will require an anatomic reduction and rigid fixation whereas a comminuted fracture is treated with indirect reduction techniques and bridge plating. This has implications for the required exposure. Anatomic reduction typically requires exposure that spans the fracture site whereas indirect reduction requires only the exposure needed for plate insertion. Potential hindrances to standard screw placement, such as a deep intercondylar box of the femoral component or the existence of proximal implants such as a hip arthroplasty stem, a short trochanteric nail, or a plate device are identified and a strategy for overcoming such issues is made. Availability of additional needed equipment, such as cables to attach the plate in the zone of an existing hip arthroplasty stem, is confirmed. Other aspects of the plan are similar regardless of the plating strategy selected. 
 
Table 23-15
ORIF of Periprosthetic Distal Femur Fractures
View Large
Table 23-15
ORIF of Periprosthetic Distal Femur Fractures
Preoperative Planning Checklist
  •  
    OR table: Radiolucent table that allows fluoroscopic imaging of the entire involved femur and knee
  •  
    Position/positioning aids: Supine using a radiolucent leg ramp to support and elevate the injured extremity
  •  
    Fluoroscopy location: Opposite side from the injured extremity with the monitor at the foot
  •  
    Equipment: Large and small fragment sets; distal femoral locking plates long enough to span the proximal fragment with at least eight screw holes; an array of reduction forceps; for interprosthetic fractures, a cable set with two cables (approximately 1.7-mm diameter)
  •  
    Tourniquet: A sterile tourniquet may be utilized for distal exposure, reduction, and plate insertion. Proximal fixation may require removal of any tourniquet
  •  
    Blood: PRBCs typed and crossmatched
X

Positioning for ORIF of Periprosthetic Distal Femur Fractures

The patient is typically positioned supine with the injured extremity pulled over to the edge of the OR table. The selected OR table should allow fluoroscopic imaging of the entire femur, especially if there are any proximal implants to be dealt with. It is helpful, but not essential that the foot of the bed be free of any hindrance to access by surgical personnel. Fracture shortening may be treated with traction applied via an assistant pulling on the limb from the foot of the bed. A bump may be placed under the ipsilateral hip to position the limb in neutral rotation. A radiolucent leg ramp is helpful to elevate the limb such that lateral radiographs are unencumbered by the contralateral leg. The entire leg and hip are prepped and draped free. To keep the entire leg in the surgical field, a sterile rather than unsterile tourniquet is utilized. The C-arm is placed on the contralateral side with the monitor at the foot of the bed. 

Surgical Approach(es) for ORIF of Periprosthetic Distal Femur Fractures

The surgical approach used for ORIF of periprosthetic distal femur fractures is essentially identical to that used for ORIF of native distal femur fractures as described in Chapter 53. Given the presence of the distal femoral prosthesis, there is obviously no need for access to the articular surface. Therefore, the standard lateral approach to the distal femur is utilized. In most cases, limited exposure to the lateral femoral condyle is supplemented with small incisions proximally to center and fix the proximal portion of the plate to the proximal fragment (Fig. 23-25). When there is a simple fracture pattern and an anatomic reduction and lag screw fixation to promote primary bone healing is the surgical tactic, a longer lateral incision and wider exposure is needed. In these cases, it is critical to avoid excessive soft tissue disruption during exposure and during reduction maneuvers. 
Figure 23-25
An intraoperative photograph (A) demonstrates limited incisions utilized for ORIF of a periprosthetic distal femur fracture.
 
B: The lateral distal femur is exposed for plate insertion and small proximal incisions are used to place proximal screws.
B: The lateral distal femur is exposed for plate insertion and small proximal incisions are used to place proximal screws.
View Original | Slide (.ppt)
Figure 23-25
An intraoperative photograph (A) demonstrates limited incisions utilized for ORIF of a periprosthetic distal femur fracture.
B: The lateral distal femur is exposed for plate insertion and small proximal incisions are used to place proximal screws.
B: The lateral distal femur is exposed for plate insertion and small proximal incisions are used to place proximal screws.
View Original | Slide (.ppt)
X

Surgical Technique for ORIF of Periprosthetic Distal Femur Fractures

Details for the surgical technique for ORIF of periprosthetic distal femur fractures depend largely on whether a bridge plating technique will be utilized in the context of a comminuted fracture, or whether a compression or neutralization plating technique is utilized for a simple fracture anatomically reduced and secured with lag screws (Table 23-16). 
 
Table 23-16
ORIF of Periprosthetic Distal Femur Fractures
View Large
Table 23-16
ORIF of Periprosthetic Distal Femur Fractures
Surgical Steps
  •  
    Expose the distal lateral femur
    •  
      For bridge plating, exposure is limited to the lateral femoral condylar region. Exposure of the fracture is neither required nor desired.
    •  
      For compression plating, exposure across the fracture zone is required to obtain an anatomic reduction of fracture fragments
  •  
    Fracture reduction
    •  
      For bridge plating, reduction is deferred until after plate insertion. The plate is generally used as a reduction aid.
    •  
      For compression plating, the fracture is reduced anatomically with care to avoid excessive soft tissue stripping
      •  
        Small fragment lag screw(s) can be helpful to maintain reduction for unencumbered plate insertion
  •  
    Plate insertion for bridge plating
    •  
      The plate is inserted submuscularly and used as a reduction aid
    •  
      The plate is aligned and provisionally secured to the proximal fragment through percutaneous or limited proximal incisions
    •  
      The distal fragment is reduced to the plate, with the plate acting as a reduction aid. Alignment relative to the distal fragment is confirmed on the AP and lateral views.
    •  
      The plate is provisionally secured to the distal fragment
    •  
      If needed, length and rotation are restored. This requires removal of the provisional proximal fixation
    •  
      The plate is aligned and secured to the proximal fragment with nonlocked screws through separate limited or percutaneous exposure
    •  
      Alignment is confirmed and adjustments made as needed prior to definitive fixation
  •  
    Plate insertion for compression plating
    •  
      The plate is inserted submuscularly
    •  
      Plate alignment relative to the proximal and distal fragments is confirmed
  •  
    Definitive plate fixation
    •  
      Distal fixation
      •  
        Multiple locked screws are inserted across the distal femoral condyle
    •  
      Proximal fixation
      •  
        Screws are inserted near and far from the fracture
  •  
    Closure
    •  
      A drain in the knee joint can facilitate postoperative knee ROM
    •  
      Standard wound closure
X
With bridge plating, a limited surgical approach is utilized. The lateral femoral condyle is exposed and the plate is slid submuscularly across the fracture. Reduction is deferred until after provisional placement of the plate. Ultimately, the plate must be aligned properly with regard to the proximal fragment and aligned properly with regard to the distal fragment to obtain a satisfactory fracture reduction. Whether the plate is secured first to the proximal fragment or first to the distal fragment is largely a matter of personal preference. It is relatively easy to align and secure the plate with the shaft fragment. However, when there is a comminuted fracture it is often difficult to judge the proximal/distal position of the plate to assure proper length reduction of the fracture. Therefore, alignment and provisional fixation of the plate to the proximal fragment with a single screw via percutaneous or limited incisions is preferred. A single nonlocked screw is usually sufficient to hold the plate well reduced to the proximal fragment. In severely osteoporotic bone, more than one screw may be required for this purpose. The distal fragment is then reduced to the plate which is already aligned and secured to the proximal fragment. The plate is used as a reduction aid. Sagittal plane alignment of the distal fragment can be adjusted using joysticks or a clamp placed from anterior to posterior on the distal fragment. Varus/valgus alignment is often difficult to establish. There is a tendency for valgus malalignment. Comparison to radiographs taken of the contralateral limb can be useful for properly recreating coronal plane alignment. 
Once coronal and sagittal plane alignment is established, the distal fragment is provisionally fixed to the plate, usually with a nonlocked screw. Proper length and rotation are confirmed. If adjustments to length or rotation are required, the provisional fixation in the proximal fragment is temporarily removed to allow these adjustments. Once satisfactory length, alignment, and rotation are confirmed, the plate is definitively secured to both the proximal and distal fragments. Multiple locking screws are inserted across the distal femoral condyle. If the prosthesis blocks placement of screws across to the medial condyle, unicortical screws are utilized. In the proximal fragment, screws are placed near and far from the fracture. If the bone quality is poor, locked screws are utilized to supplement nonlocked screws. Plate length should allow at least eight holes to cover the proximal shaft fragment. 
When dealing with a simple fracture pattern, an anatomic reduction and provisional fixation of the fracture is usually accomplished prior to plate fixation (Fig. 23-26). This generally requires a larger surgical exposure. Great care must be taken to avoid excessive stripping when attempting to anatomically reduce the fracture. Once the fracture is anatomically reduced, it can be held with reduction clamps or countersunk lag screws. Lag screws, in contrast to clamps, allow unencumbered plate insertion and fixation. The plate is applied to the lateral femur with the proximal portion of the plate slid along the lateral femur submuscularly. Fixation of the plate to the already reduced fracture must assure that the fracture reduction is not disturbed. If there is a mismatch between the contour of the plate and the contour of the bone, nonlocked screw fixation runs the risk of disrupting the reduction. In this scenario, either the plate must be recontoured to match the bone, or fixation with locked screws can be utilized. In addition, it is often possible to get additional lag screw fixation across the fracture through the plate. 
Figure 23-26
 
A relatively simple spiral periprosthetic fracture of the distal femur (A) is reduced anatomically and provisionally secured with small fragment lag screws (B) to allow unencumbered definitive plate fixation (C).
A relatively simple spiral periprosthetic fracture of the distal femur (A) is reduced anatomically and provisionally secured with small fragment lag screws (B) to allow unencumbered definitive plate fixation (C).
View Original | Slide (.ppt)
Figure 23-26
A relatively simple spiral periprosthetic fracture of the distal femur (A) is reduced anatomically and provisionally secured with small fragment lag screws (B) to allow unencumbered definitive plate fixation (C).
A relatively simple spiral periprosthetic fracture of the distal femur (A) is reduced anatomically and provisionally secured with small fragment lag screws (B) to allow unencumbered definitive plate fixation (C).
View Original | Slide (.ppt)
X

Postoperative Care for ORIF of Periprosthetic Distal Femur Fractures

There is generally no need for postoperative immobilization. Early rehabilitation is concentrated on patient mobilization and knee ROM. Weight bearing is protected to some degree for approximately 6 to 8 weeks. Initial weight-bearing restrictions are toe-touch for balance or up to 50% weight bearing if the bone quality and fixation were both optimal. Therapy for knee ROM, transfer training, and use of assist devices are initiated immediately postoperatively. It is important to know baseline knee ROM limits to determine postoperative goals. Continuous passive motion (CPM) for knee ROM is usually familiar to this patient population given their prior knee arthroplasty. The use of CPM after periprosthetic supracondylar femur fracture is of unknown long-term benefit but can be useful to obtain early functional ROM. CPM to 90 degrees of flexion can generally be obtained within 48 hours of surgery if any knee joint hemarthrosis is decompressed with a drain, the limits of flexion are advanced 10 degrees three times daily, and adequate postoperative analgesia is provided. 
Based on progressive clinical and radiographic signs of fracture healing, weight bearing is gradually advanced. Full weight bearing is typically accomplished by 6 to 8 weeks postoperatively and at this time formal strengthening and gait training therapy are useful. 

Potential Pitfalls and Preventative Measures for ORIF of Periprosthetic Distal Femur Fractures

One of the most common pitfalls during ORIF of distal femur fractures is reduction in valgus (Table 23-17). True AP radiographs and comparison to the contralateral limb should be used to assure proper alignment. Most locked plating systems have screw(s) that are designed to be 95 degrees from the long axis of the plate shaft. When these screws are parallel to the articular surface, 5 degrees of valgus results. In the sagittal plane, apex posterior malreduction is common. Joysticks or clamps in the distal fragment can be used to manipulate the articular segment into proper alignment. Loss of distal fixation, a concern when the femoral component blocks screw placement, is fortunately uncommon. Use of multiple locking screws and the largest diameter screws available will minimize this potential problem. Proximal fixation is optimized with the use of relatively long plates, eight or more holes covering the proximal fragment secured with at least four screws. Locked screws are utilized in the proximal fragment when bone stock is poor. The mechanics of the construct should be optimized to promote the desired method of fracture healing. Simple fractures are fixed with relatively rigid constructs with lag screws to promote primary bone healing. More comminuted fractures are managed with bridge plating constructs that provide relative stability and promote secondary bone healing. 
 
Table 23-17
ORIF of Periprosthetic Distal Femur Fractures
View Large
Table 23-17
ORIF of Periprosthetic Distal Femur Fractures
Potential Pitfalls and Preventions
Pitfalls Preventions
The femoral prosthesis is found intraoperatively to have a closed intercondylar box obviating retrograde nailing Preoperative identification of femoral prosthesis geometry from past surgical records and x-rays
Intraoperative notch view of the knee prior to initiation of retrograde nailing
Axial shortening of the fracture Compare leg lengths preoperatively with a radiopaque ruler
Muscle paralysis can aid in restoring length
Loss of reduction between reaming and nail placement Recreate reduction maneuvers used to obtain reduction for guidewire placement for reaming and nail placement
Fracture malalignment Starting point and starting trajectory are colinear with the long axis of the distal fracture fragment
Blocking screws used to obtain and maintain colinearity of nail with long axis of distal fracture fragment
Secondary loss of fracture alignment Use of blocking screws to help maintain fracture alignment, especially in osteoporotic bone
Use of multiple fixed angle distal interlocking screws
Painful medial interlocking screws Careful measurement of screw length without reliance on AP radiographs
Confirm screw length with “roll-over” fluoroscopic view
Knee pain from intra-articular nail protrusion Confirm countersinking of nail by direct vision, palpation, and true lateral knee radiograph
Do not rely on AP radiograph of knee to judge nail position relative to articular surface
X

Outcomes of ORIF for Periprosthetic Distal Femur Fractures

Older methods of plate fixation of supracondylar femur fractures that included traditional condylar buttress plates are prone to complications. These non–fixed-angle implants are especially prone to varus collapse when comminution is present. Davison56 reported more than 5 degrees of collapse to occur in 11 of 26 (42%) such comminuted distal femur fractures. These problems can be magnified in patients with fractures associated with a TKA as these patients are often elderly with osteoporotic bone making stable internal fixation even more unreliable. This is further confounded by a potentially reduced ability to gain bicondylar screw purchase because of interference of the TKA prosthesis. Figgie et al.76 reported failure of internal fixation in 5 of 10 patients with periprosthetic femur fractures above a TKA treated with traditional plating methods and Merkel and Johnson186 reported satisfactory results in only three of five such patients. Traditional fixed-angle plate constructs, such as 95-degree condylar plates and blade plates, reduce the risk for varus collapse of distal femur fractures when compared to traditional nonlocked plating, but have limited application for fractures about a TKA prosthesis because of potential interference of the femoral component. In the setting of relatively proximal supracondylar fractures, where there is sufficient bone for seating of a blade, 95-degree condylar blade plating using indirect reduction techniques has been shown to yield very good results. Kolb et al.139 applied this technique in 21 cases, four of which were supplemented with bone graft and three were supplemented with bone cement. All but one fracture healed after the index procedure with only one case of varus malalignment. 
Anatomically contoured locking plates for the distal lateral femur have potential advantages for the fixation of supracondylar femur fractures associated with TKA. In contrast to traditional 95-degree plate devices, locking plates offer multiple, rather than single, distal fixed-angle screw options. Ricci et al.230 showed that at least two such locked screws were typically able to be placed across to the medial condyle despite the presence of a TKA femoral component. When bicondylar screw fixation was blocked by the TKA, unicondylar locked screws were utilized. This combination of bicondylar and unicondylar locked screw fixation provided excellent distal fixation. In the series of Ricci et al.230 no distal fixation failures occurred. Another study from the same group showed that extreme distal fractures, those that extended to the anterior flange of the TKA femoral component or beyond, treated with locked plates have similar results as more proximal fractures.264 These results are consistent with those of other series of locked plate fixation of native distal femur fractures247,249 indicating that the presence of the TKA femoral component has little effect of the outcome of supracondylar distal femur fractures treated with locked plates. The use of polyaxial locked screws has also shown promising results (90% union) for these fractures with a purported advantage of better ease of screw insertion to avoid interference of the TKA component.72 
Although locked plate fixation has become the de facto standard method for ORIF at many centers, nonunion and implant failure rates for this method of fixation remain a concern. Hoffmann et al.,115 in a series of 36 fractures in patients with mean age of 73.2 years treated with locked plates at two trauma centers, reported nonunion in 22.2% of cases and implant failure in 8.3%. They noted that surgical handling of the soft tissues affected the risk of nonunion. Patients treated with submuscular plating had a reduced risk of nonunion compared to those treated with an extensive lateral approach. Ricci et al.,230 in a series of 22 patients treated with locked distal femoral plates, also showed a relatively high nonunion rate of 14%. The three patients with nonunion were insulin-dependent diabetics who were also obese. Fulkerson et al.85 also had a high complication rate (33%) after treatment of 18 supracondylar femur fractures above a TKA with a first generation locking plate. These included plate failure (n = 1), delayed union (n = 2), nonunion (n = 2), and component loosening (n = 1). In contrast, Anakwe et al.6 and Large et al.150 had no nonunions among a total of 40 patients treated with locked plating and Kolb et al.138 reported just one nonunion among 19 patients at midterm follow-up of 46 months. 
Head-to-head comparisons of modern locked plating and retrograde nailing have shown similar results for the two methods of treatment. A systematic review of 415 cases showed locked plating and retrograde IMN to provide superior results compared to conventional nonlocked plating.113 Overall, the nonunion rate was 9%, the fixation failure rate was 4%, the infection rate was 3%, and the revision surgery rate was 13%. Retrograde nailing was found to offer relative risk reductions for nonunion (87%) and revision surgery (70%) compared to traditional nonlocked plating. Locked plating showed nonsignificant trends toward similar risk reductions compared to traditional plating (57% for nonunions, 43% for revision surgery). Other retrospective comparative studies of LP or IMN of periprosthetic femur fractures above a TKA have showed varying results. Hou et al.117 reported similar nonunion (9% for LP and 6% for IMN) and malunion (9% for LP and 11% for IMN) rates for the two methods, whereas Platzer et al.217 found better union rates with IMN and better alignment after LP.217 
Given the modest nonunion rates reported after locked plating of distal femur periprosthetic fractures, it is not surprising that there is a parallel reported occurrence of implant failure. As with all internally fixed fractures, there is a race between fracture healing and implant failure. For plate constructs implant failure may occur in one of three zones: the zone of distal fragment fixation, the zone of fracture (the so-called working length of the plate), or the zone of the proximal fragment. The weak link of locked plate constructs has been shown to be the plate failure over the zone of fracture or screw failure in the proximal fragment in up to 33% of cases.113,220,230,264 Of note, three of the four proximal screw failures in one series occurred when exclusively nonlocking screws were used in the shaft fragment.230 This study was among the first to describe modern “hybrid” locked fixation, where nonlocked and locked screws were used in the same construct. Only one failure occurred among the 14 cases where locking screws supplemented nonlocked fixation in the shaft, this being a patient with diabetes and obesity who developed an aseptic nonunion. 
Inserting nonlocked screws prior to locked screws in any given fragment during hybrid locked plating allows the plate to be used as a reduction aid where the contour of the plate helps dictate the reduction in the coronal plane. Malreductions using the hybrid locked-plating technique were present in only 2 of 22 cases (9%).230 This compares favorably with the reduction (6% to 20% malreductions) reported with internal fixator systems (such as LISS) where exclusive use of locked screws makes reduction independent of plate contour.143,150,174,247,249 
Biomechanical investigations suggest that locked screws in the diaphysis may protect from this type of screw failure, especially in osteoporotic bone.67,211 

Intramedullary Nailing of Periprosthetic Distal Femur Fractures

Retrograde intramedullary nailing has evolved as a satisfactory treatment option for fixation of supracondylar femur fractures that are not associated with TKA. This fixation method is advantageous because of the indirect nature of the fracture reduction and associated minimization of soft tissue disruption about the fracture. However, problems obtaining stable fixation with intramedullary nails in patients with wide metaphyseal areas, with osteopenia, or both can lead to loss of fixation and malalignment.4 When a TKA is present, the potential difficulties of retrograde nailing of supracondylar femur fractures are also increased (Fig. 23-27). As previously described, some TKA designs, because of a closed or narrow intercondylar notch, preclude the use of retrograde nails or limit their maximum diameter, respectively. Furthermore, the specific prosthesis type may be unknown at the time of fracture fixation. In these cases, the choice of an anterior surgical approach used for retrograde nailing may need to be aborted in favor of a lateral approach for plate fixation if a nonaccommodating prosthesis is encountered. Despite these potential pitfalls, retrograde IMN can be successfully applied to periprosthetic supracondylar femur fractures that have adequate distal bone stock and is the preferred method of treatment by some authors (Figs. 23-27 C and D).91 
Figure 23-27
Retrograde nailing of distal femur fractures with wide metaphyseal regions (A) runs the risk of malalignment (B).
 
Proper technique requires the nail be aligned with the axis of both the proximal and distal fragments. The isthmus of the femur helps align long nails within the proximal fragment, but it is incumbent upon the surgeon to establish alignment in the distal fragment. With attention to detail, successful alignment can be accomplished even with distal fractures (C). Nails with multiple distal locking options are recommended (D). (C & D, courtesy of Paul Tornetta, III, MD).
Proper technique requires the nail be aligned with the axis of both the proximal and distal fragments. The isthmus of the femur helps align long nails within the proximal fragment, but it is incumbent upon the surgeon to establish alignment in the distal fragment. With attention to detail, successful alignment can be accomplished even with distal fractures (C). Nails with multiple distal locking options are recommended (D). (C & D, courtesy of Paul Tornetta, III, MD).
View Original | Slide (.ppt)
Proper technique requires the nail be aligned with the axis of both the proximal and distal fragments. The isthmus of the femur helps align long nails within the proximal fragment, but it is incumbent upon the surgeon to establish alignment in the distal fragment. With attention to detail, successful alignment can be accomplished even with distal fractures (C). Nails with multiple distal locking options are recommended (D). (C & D, courtesy of Paul Tornetta, III, MD).
View Original | Slide (.ppt)
Figure 23-27
Retrograde nailing of distal femur fractures with wide metaphyseal regions (A) runs the risk of malalignment (B).
Proper technique requires the nail be aligned with the axis of both the proximal and distal fragments. The isthmus of the femur helps align long nails within the proximal fragment, but it is incumbent upon the surgeon to establish alignment in the distal fragment. With attention to detail, successful alignment can be accomplished even with distal fractures (C). Nails with multiple distal locking options are recommended (D). (C & D, courtesy of Paul Tornetta, III, MD).
Proper technique requires the nail be aligned with the axis of both the proximal and distal fragments. The isthmus of the femur helps align long nails within the proximal fragment, but it is incumbent upon the surgeon to establish alignment in the distal fragment. With attention to detail, successful alignment can be accomplished even with distal fractures (C). Nails with multiple distal locking options are recommended (D). (C & D, courtesy of Paul Tornetta, III, MD).
View Original | Slide (.ppt)
Proper technique requires the nail be aligned with the axis of both the proximal and distal fragments. The isthmus of the femur helps align long nails within the proximal fragment, but it is incumbent upon the surgeon to establish alignment in the distal fragment. With attention to detail, successful alignment can be accomplished even with distal fractures (C). Nails with multiple distal locking options are recommended (D). (C & D, courtesy of Paul Tornetta, III, MD).
View Original | Slide (.ppt)
X

Preoperative Planning for IM Nailing of Periprosthetic Distal Femur Fractures

In general, planning for retrograde nailing of periprosthetic distal femur fractures follows that described for standard retrograde nailing in Chapter 53 Femoral Shaft Fractures (Table 23-18). Ideally, the femoral component type and the intercondylar dimensions are identified from prior operative records to assure that retrograde nailing through the intercondylar notch of the femoral component is possible. If documentation is unobtainable, reference sources can help identify the component based on radiographic profiles and provide details of the intercondylar notch dimensions.111 It is very unusual to unexpectedly encounter a loose femoral component. However, if there is clinical suspicion for component loosening, then the preoperative plan should consider the contingency for component revision or distal femoral replacement. 
Table 23-18
Intramedullary Nailing of Periprosthetic Distal Femur Fractures
Preoperative Planning Checklist
  •  
    Assessment of the femoral prosthesis: Compatibility of the femoral prosthesis with retrograde nailing is confirmed
  •  
    OR table: Radiolucent table that allows fluoroscopic imaging of the entire involved femur and knee and allows unencumbered access to the foot of the table
  •  
    Position/positioning aids: Supine using a radiolucent triangle
  •  
    Fluoroscopy location: Opposite side from the injured extremity with the monitor at the head
  •  
    Equipment: Retrograde nailing set and associated implants. Femoral distractor available
  •  
    Tourniquet: A sterile tourniquet may be utilized for obtaining distal exposure, the starting point, and instrumentation of the distal fragment. Proximal fixation usually requires removal of any tourniquet
  •  
    Blood: PRBCs typed and crossmatched
X

Positioning and Surgical Approach for IM Nailing of Periprosthetic Distal Femur Fractures

Patient positioning, typically supine, and the surgical approach for IMN of periprosthetic distal femur fractures is essentially identical to that for retrograde nailing of native femur fractures as discussed in Chapter 53 Femoral Shaft Fractures. Of course, consideration must be given to old incisions about the knee from the prior knee arthroplasty. The longitudinal midline incision typically used for TKA is usually well positioned for the standard approach for retrograde nailing. 

Surgical Technique for IM Nailing of Periprosthetic Distal Femur Fractures

As with nailing any long bone, the first critical step for retrograde nailing of distal femur fractures is securing the location and trajectory of the starting point in the distal fragment (Table 23-19). The location of the starting point is in line with the long axis of the distal fragment, or slightly off this line based on the geometry of the selected nail. On the AP view, a starting point located on the center axis line is typically just medial to the center of the intercondylar notch. On the lateral view, a starting point on the center axis line corresponds to the apex of Blumensaat line or just anterior to it. Because most retrograde nails have an apex posterior bend at the driving end, the starting point can be just posterior to the center axis line on the lateral view. Unique to retrograde nailing of periprosthetic fractures are the constraints imposed by the location of the femoral component intercondylar space. The location of the prosthetic notch may force a starting location from the ideal points discussed above. 
Table 23-19
Intramedullary Nailing of Periprosthetic Distal Femur Fractures
Surgical Steps
  •  
    Confirm open intercondylar box with notch view fluoroscopic radiograph
  •  
    Confirm muscle paralysis is complete
  •  
    Midline surgical incision and medial parapatellar arthrotomy
  •  
    Place starting guidewire colinear with the long axis of the distal femoral fracture fragment
  •  
    Insert stiff starting reamer over guidewire and adjust trajectory
  •  
    Reduce fracture with manual forces (e.g., longitudinal traction and gentle manipulation with the use of strategically placed bumps) and be prepared to use accessory means such as blocking screws, a femoral distractor, or Schanz pin joysticks.
  •  
    Pass guidewire across reduced fracture to a location above the lesser trochanter
  •  
    Depth gauge measurement to determine nail length with fracture out to proper length
  •  
    Ream over guidewire to a diameter 0.5 to 1.5 mm beyond the initiation of cortical chatter at the femoral isthmus
  •  
    Select appropriate size nail with determined diameter 1 to 1.5 mm smaller than largest reamer diameter
  •  
    Assemble nail to insertion handle and confirm alignment of drill sleeves for interlocking screws
    •  
      Insert nail over guidewire
    •  
      Confirm final location of nail with fluoroscopic radiographs proximally and distally
    •  
      Confirmation of distal nail location, countersunk beyond the articular margin, is performed with direct vision, palpation, and/or true lateral radiographs of the knee
  •  
    Confirm satisfactory angular fracture reduction before interlocking. Be prepared to remove nail and place blocking screws if reduction is unsatisfactory
  •  
    Perform multiple distal interlocking and assure screws are of appropriate length so as to avoid medial prominence
  •  
    Confirm satisfactory rotational fracture reduction and satisfactory length
  •  
    Perform proximal interlocking
X
The starting trajectory should be collinear with the long axis of the femur in both the sagittal and coronal planes. Given the often coexistent osteopenic bone and wide metaphyseal areas in the patient population with periprosthetic fractures, an initial opening reamer passed in an ideal trajectory will not necessarily guarantee that subsequent reamers or the retrograde nail will follow the same path. Therefore, the surgeon must be prepared to utilize supplementary techniques to assure that the nail is aligned properly within the distal fragment. We prefer the use of blocking screws. These screws are placed anterior to posterior to control varus/valgus alignment and from lateral to medial to control flexion/extension alignment. The blocking screws should be placed relatively near the fracture to optimally affect alignment. Additional technical details of retrograde femoral nailing and blocking screw placement can be found in multiple chapters throughout this book including Chapter 7 – Principles of Internal Fixation, Chapter 54 – Distal Femur Fractures, and Chapter 57 – Tibia and Fibula Fractures

Postoperative Care for IM Nailing of Periprosthetic Distal Femur Fractures

Patients are mobilized as soon as possible postoperatively. Weight bearing is typically protected for 4 to 6 weeks after retrograde nailing of a comminuted distal femur fracture in osteoporotic patients, the typical scenario for periprosthetic distal femur fractures. Weight bearing can be initiated earlier when there is confidence in the distal fixation and bone quality is good. CPM is generally initiated in the recovery room and is usually better tolerated if the knee is decompressed with a suction drain. The goals of CPM must not assume full knee ROM was achievable at baseline. A careful history of prefracture knee function helps identify reasonable goals for postoperative ROM and function. Weight bearing is advanced based on clinical and radiographic evidence of progressive fracture healing. 

Potential Pitfalls and Preventative Measures for IM Nailing of Periprosthetic Distal Femur Fractures

One of the most disheartening potential pitfalls of retrograde nailing of periprosthetic distal femur fractures is unexpectedly finding a closed or a narrow intercondylar box of the femoral component that prevents passage of the retrograde nail (Table 23-20). Prevention of this situation is certainly preferred to managing it intraoperatively. In the absence of accurate documentation of the knee arthroplasty design, an intraoperative notch view can be used to confirm an open intercondylar notch. In situations where there is such uncertainty, the preoperative plan should include the contingency for alternative fixation methods than retrograde nailing, including immediate availability of all equipment and implants. 
Table 23-20
Intramedullary Nailing of Periprosthetic Distal Femur Fractures
Potential Pitfalls and Preventions
Pitfalls Preventions
Fracture malreduction, typically valgus Intraoperative evaluation of fracture alignment with true AP and true lateral radiographs
Comparison to contralateral limb radiographs
Clinical comparison to the contralateral limb
Loss of distal fixation Maximize the number and diameter of bicondylar locking screws in distal fragment
Unicondylar locking screws may be required if bicondylar screws are blocked by the prosthesis
Loss of proximal fixation Use of long plate, eight or more holes spanning proximal fragment
Secure with at least two screws near the fracture and two screws far from fracture
Inadequate biomechanics of fixation construct Identify the desired mode of fracture healing, primary or secondary, and design construct with appropriate mechanics
X
Obtaining and maintaining satisfactory fracture alignment is often difficult in the setting of a periprosthetic fracture. The patient population that sustains these injuries often has substantial osteoporosis, leaving the metaphyseal region of the distal fracture fragment relatively vacuous and often incapable of supporting a proper nail trajectory. Even when the starting guidewire and opening portal are perfectly aligned, the nail often migrates to a different trajectory leading to malalignment of the fracture. In such cases, placement of blocking screws helps obtain and maintain proper position of the nail, centered along the long axis of the distal fragment, and in turn results in a satisfactory fracture reduction. With the use of long retrograde nails that span the isthmus of the femur, alignment of the nail within the proximal fragment is infrequently an issue. The isthmus, located at the junction of the proximal and middle thirds of the femoral diaphysis, serves to center the nail in the proximal fragment. When the nail is colinear with the long axis of both the distal and proximal fragments, a proper reduction, with regard to varus/valgus and flexion/extension, will result. Secondary loss of reduction can occur as a result of poor fixation within the distal fragment, also owing to the presence of substantial osteoporotic bone. As described earlier, blocking screws can help maintain reduction as they stabilize the nail relative to the surrounding bone. When blocking screws are used for this purpose, screws on both sides of the nail, medial and lateral to control varus/valgus and anterior and posterior to control flexion/extension, are beneficial. Whereas blocking screws used purely to control alignment are placed only on one side of the nail, for example, lateral side to control valgus and anterior side to control extension deformities. It is recommended to place as many interlocking screws as possible (typically three or four depending upon the nailing system selected) in various planes to support distal fixation in osteoporotic bone. Interlocking screws should be bicortical to capture the strength of the cortical shell, but care should be taken to avoid excessively long screws. AP radiographs should not be relied upon to judge screw length because of the trapezoidal shape of the distal femur. A screw that is relatively anterior in the distal femur, which is the same width as the distal femoral condyles, will protrude through the medial distal femur by 1 cm or more and cause pain. Careful length measurement with a depth gauge and confirmation of screw length with roll-over fluoroscopic views can help avoid this potential problem. Just as proper views are necessary to judge interlocking screw length, proper views are needed to judge position of the distal end of the nail relative to the articular surface of the prosthesis. Again, AP views should not be relied upon for this purpose. A true lateral of the knee is necessary to judge nail position relative to the knee prosthesis. Even with a true lateral, confirmation of proper positioning of the nail can be obscured by the radio-opaque prosthesis. In such scenarios, direct vision and/or palpation should be used to assure the nail end is not too proud. A nail that protrudes into the knee can interfere with patellofemoral motion and even damage the patellar component. 

Outcomes of IM Nailing for Periprosthetic Distal Femur Fractures

Most studies of periprosthetic supracondylar femur fractures treated with retrograde nailing are small retrospective series. Reported union rates are generally favorable, especially in comparison to locked plating. However, the risk of malunion after retrograde nailing is high. 
Four small series (14 or less patients) of periprosthetic supracondylar femur fractures treated with retrograde nailing each reported 100% union.41,91,104 Alignment at healing is variable as this is one of the main technical challenges of this treatment method: Han et al. had no malalignment greater than 10 degrees. They paid particular attention to alignment and used cerclage fixation to improve reduction in three of eight cases when closed reduction resulted in greater than or equal to 5 degrees of malalignment.104 Malunion of 35-degree valgus requiring revision to a stemmed TKA occurred in 1 of 10 cases reported by Gliatis.91 Another study of 14 patients reported valgus of 8 to 12 degrees in three cases, 15-degree extension in one, and 50% posterior translation in another.41 The malalignment seen in these series may, in part, be related to the use of short nails, which, because they do not benefit from the stability and alignment control that comes from passing the nail across the femoral isthmus, are not currently recommended for treatment of distal femur fractures. 
Wick et al.292 found comparable results for retrograde nailing and locked plating of periprosthetic distal femur fractures in a small comparative series of nine fractures each. They noted that locked plates were preferred in cases with osteoporotic bone. 
Recent advances in nail design that provide multiple interlocks at various angles may provide improved fixation of the distal segment and may therefore expand the indications for this technique. 

Revision Total Knee Arthroplasty for Periprosthetic Distal Femur Fractures

For patients with loose implants associated with a supracondylar fracture, revision is typically considered. Bony defects, areas of osteolysis, osteopenia, and short periarticular fragments all pose challenges to a successful revision arthroplasty in this setting. In elderly patients, distal femoral replacement “megaprostheses” are often required to reconstruct massive bony defects. Attention to specific technical details is necessary for a successful result, and the surgeon undertaking such reconstructions should be experienced in both arthroplasty and fracture management techniques. In patients with a loose implant or a history of prefracture knee pain, the routine preoperative evaluation of these patients should include a complete blood count with manual differential, sedimentation rate, C-reactive protein serologies, and a knee aspiration to exclude occult infection. 
If available, the operative note from the original arthroplasty should be obtained. This is especially important if isolated component revision is contemplated. Older implant designs may not offer varying degrees of constraint, augmentations, polyethylene insert sizes, etc., and thus compatibility issues may necessitate complete arthroplasty revision. Previous incisions and the status of the soft tissues should be circumferentially evaluated and the neurovascular status of the limb should be carefully documented. Wounds are especially important around the knee since the probability of flap necrosis and wound problems is much higher around the knee than the hip. Great care should be taken to prevent narrow, acutely angled skin bridges between connecting incisions and to develop full thickness flaps during dissection. As best as possible, prior incisions should be used. If a distinct incision is needed, appropriate separation of the incisions should be maintained to provide a suitable skin bridge. The status of the extensor mechanism is very important for treatment and prognosis and this should be determined during evaluation. 
The need for revision TKA secondary to periprosthetic fracture has become less common in our practice with the advent of improved internal fixation devices such as locked plates. Typically, revision arthroplasty is reserved for fractures around a loose prosthesis, fractures with inadequate bone stock to allow for stable internal fixation, or for recalcitrant supracondylar nonunions which require resection and megaprosthesis implantation (Fig. 23-28). Surgeons who treat periprosthetic fractures around a TKA must have the expertise and technical support to be able to perform either long-stemmed revision TKA or revision to a megaprosthesis. Bony defects secondary to comminution, multiple previous procedures, the presence of broken hardware, and the presence of deformity all may present technical challenges to a successful outcome. 
Figure 23-28
 
A: A radiograph of a periprosthetic distal femoral nonunion. B: An intraoperative photograph shows extensive bone loss. C, D: This was treated with a distal femoral replacement. (Courtesy of Hari Parvataneni, MD).
A: A radiograph of a periprosthetic distal femoral nonunion. B: An intraoperative photograph shows extensive bone loss. C, D: This was treated with a distal femoral replacement. (Courtesy of Hari Parvataneni, MD).
View Original | Slide (.ppt)
A: A radiograph of a periprosthetic distal femoral nonunion. B: An intraoperative photograph shows extensive bone loss. C, D: This was treated with a distal femoral replacement. (Courtesy of Hari Parvataneni, MD).
View Original | Slide (.ppt)
Figure 23-28
A: A radiograph of a periprosthetic distal femoral nonunion. B: An intraoperative photograph shows extensive bone loss. C, D: This was treated with a distal femoral replacement. (Courtesy of Hari Parvataneni, MD).
A: A radiograph of a periprosthetic distal femoral nonunion. B: An intraoperative photograph shows extensive bone loss. C, D: This was treated with a distal femoral replacement. (Courtesy of Hari Parvataneni, MD).
View Original | Slide (.ppt)
A: A radiograph of a periprosthetic distal femoral nonunion. B: An intraoperative photograph shows extensive bone loss. C, D: This was treated with a distal femoral replacement. (Courtesy of Hari Parvataneni, MD).
View Original | Slide (.ppt)
X
Revision TKA with intramedullary femoral stems that engage the diaphysis and simultaneously stabilize the fracture can be used. Cemented stems may be used, but care must be taken to prevent extrusion of cement into the fracture site. Allograft struts with cerclage wiring can be used to reinforce the stability provided by a long stem prosthesis. It is very unusual, however, to have distal femoral bone stock that is inadequate for internal fixation yet adequate for formal revision. The ideal indication for long stem revision TKA would be the presence of adequate bone stock in the face of a supracondylar fracture with a grossly loose femoral component.11,71,217 
Revision arthroplasty is typically chosen for fractures around loose implants and fractures of the distal femur with distal fragments that offer no reasonable opportunity for internal fixation. Revision of femoral components typically requires metal augmentation because of the inevitable bone deficiency associated with component removal. Stems should be used routinely, and it is recommended that the stem engage the femoral diaphysis both for alignment and fixation reasons. Commercially available metaphyseal sleeves and trabecular metal cones can be useful for managing capacious metaphyseal defects. These implant types have limited published data on outcomes but do offer increased revision options including a combination of cemented and noncemented fixation and modular options allowing increased constraint and stemmed implants mated to the metaphyseal fixation. These hybrid constructs may offer improved longevity over cemented-only designs. It should be noted that implants with increased varus–valgus constraint and hinged implants should be available, since ligamentous insufficiency is common in this setting. More commonly, with a distal femoral fracture above a loose implant, there is simply not enough bone to support a traditional revision, even with the use of diaphyseal engaging stems. This situation is not uncommon in the elderly, low-demand patient. In these cases, a modular megaprosthesis (distal femoral replacement) is performed. Careful dissection of the residual distal femoral bone is performed to avoid vascular injury. Various modular segments are available to manage metaphyseal bone loss because of fracture comminution, yet still allow restoration of appropriate leg length, limb alignment, and knee stability. Cement fixation is typically used in this setting. 

Preoperative Planning, Positioning, Surgical Approaches, and Surgical Technique for Revision TKA for Periprosthetic Distal Femur Fractures

Incision planning is essential in preventing skin necrosis or wound issues (Table 23-21 and 23-22). The prior incision should be used if possible and if it allows extensile approaches. If a separate incision is needed, an adequate skin bridge should be maintained. If the surgical incision contacts or crosses another, the junctional area should not have too acute an angle. Skin flaps should be of full thickness. A full thickness anteromedial capsular flap should be maintained to reduce the risk of wound-healing problems in this area. 
Table 23-21
Revision Total Knee Arthroplasty for Periprosthetic Distal Femur Fractures
Preoperative Planning Checklist
  •  
    OR table: Radiolucent
  •  
    Position/positioning aids: Knee bumps for working in midflexion and full flexion
  •  
    Fluoroscopy: Usually needed for hardware removal or to confirm adequate bypass of stress risers
  •  
    Equipment: Hardware removal equipment, flexible osteotomes, high speed burr, curettes, and appropriate implant options including stem options, implant constraint, backup options
  •  
    Tourniquet (sterile/nonsterile): Sterile for distal femoral replacements or any procedure requiring exposure up to the proximal thigh. Nonsterile tourniquet otherwise
  •  
    Confirm incision and prior wound conflicts as well as infection workup
X
Table 23-22
Revision Total Knee Arthroplasty for Periprosthetic Fractures About the Knee
Surgical Steps
  •  
    Incision planning and placement: Full thickness flaps
  •  
    Extensile approach: Quadriceps snip or tibial tubercle osteotomy if needed
  •  
    Assess collateral ligaments to determine level of constraint needed: A hinged prosthesis would be necessary with megaprosthesis that removes the collateral ligaments
  •  
    Evaluate bone stock to determine if metaphyseal, diaphyseal, or combined fixation is needed: Use augments, sleeves, stems, and/or megaprosthesis as needed
  •  
    Retain patellar component unless grossly loose
  •  
    Both femoral and tibial component revision may be needed if additional constraint is used
  •  
    Femoral rotation should be marked on the remaining femur before removal of the distal femur. The joint line can be restored by referencing the patella
  •  
    Trialing should be done carefully to evaluate soft tissue tension, joint line, stability of the flexion gap, patellar tracking, and the ability to close the soft tissue sleeve
X
The extensor mechanism should be protected and continuously evaluated for risk of rupture. The medial and lateral gutters must be recreated. Peripatellar and infrapatellar scar must be excised to mobilize the extensor mechanism. A quadriceps snip or tibial tubercle osteotomy should be performed if there is undue tension on the extensor mechanism or inadequate exposure. 
Once an adequate exposure is obtained, the status of the patellar component, tibial and femoral bone stock, and the status of the collaterals are determined. At this point, decisions about metaphyseal/diaphyseal/combined fixation, length of the stems needed, augments, and need for metaphyseal sleeves or megaprosthesis are made. 
Typically the patellar component should be retained unless loose or defective. If a megaprosthesis is required, subperiosteal dissection of the bone to be removed should be done for safety and to preserve a good soft tissue sleeve. The joint line level can be determined based on the position of the patella. The femoral and tibial rotation should be marked on the remaining diaphysis before removal of the metaphysis. 
Trialing should be done to evaluate soft tissue tension, position of the joint line, patella tracking, stability of the gaps, and the tension on the soft tissue sleeve. If the trials are too bulky and closure is difficult, downsizing the implant and shortening the construct can help in closure. 
If cemented implants are used, they can be cemented in separate phases to allow for better control of implant position. For cases where there is diaphyseal-only noncemented fixation, cerclage wires at the opening will help to prevent fracture propagation. 
The tourniquet should be deflated and hemostasis should be obtained before closure to reduce hematomas in the large potential spaces. 
After closure, the skin should be checked carefully in extension and flexion for vascularity. 

Postoperative Care After Revision TKA for Distal Femur Fracture

Weight bearing is dictated by fixation quality and stability. ROM should be restricted until it is clear that the wound has adequate vascularity and is healing well. A hinged knee brace may provide additional external protection during the recovery period while the patient regains strength and improved gait. 

Potential Pitfalls and Preventative Measures After Revision TKA for Distal Femur Fracture

Revision arthroplasty is a demanding procedure that has many potential issues at various stages (Table 23-23). In the setting of a periprosthetic fracture, the soft tissue envelope may be compromised more so than in the setting of a standard revision. Great care must be taken to avoid skin necrosis by carefully planning incisions and using meticulous surgical technique. As with any TKA revision, adequate exposure and recreating of the normal medial and lateral gutter tissue planes facilitate component removal and implantation, maximizes ROM potential, and minimizes the need for excessive soft tissue retraction. Stable component fixation may require specialized devices such as metaphyseal sleeves, augments, long stems, and highly constrained or hinged components, and/or megaprostheses. A full complement of such fixation options should be available. 
Table 23-23
Revision Total Knee Arthroplasty for Periprosthetic Distal Femur Fractures
Potential Pitfalls and Preventions
Pitfalls Preventions
Skin necrosis Careful incision planning
Full thickness skin flaps
Restrict postoperative flexion if needed
Inadequate exposure Recreate gutters, excise peripatellar and infraptellar scar tissue
Quadriceps snip or tibial tubercle osteotomy
Inadequate fixation options Careful preoperative planning and implant selection
Availability of metaphyseal sleeves, stems, augments, and/or megaprosthesis
Instability Plan adequate constraint options including varus/valgus constraint options and hinged prosthesis. Pay special attention to flexion laxity
X

Outcomes of Revision Total Knee Arthroplasty for Periprosthetic Distal Femur Fractures

Most of the clinical data evaluating the outcomes of a simultaneous revision arthroplasty with intramedullary stem fixation of a supracondylar fracture have been gathered from the treatment of distal femoral nonunions in this situation. Kress et al.144 reported a small series of nonunions about the knee treated successfully with revision and uncemented femoral stems with bone grafting. They achieved union in 6 months. 
Distal femoral replacement “megaprostheses” have been used for salvage of failed internal fixation of supracondylar periprosthetic femur fractures. The long-term results of the kinematic rotating hinge prosthesis for oncologic resections about the knee have been good, with a 10-year survivorship of approximately 90%. As their success becomes more predictable, the indications for megaprostheses are expanding. Elderly patients with refractory periprosthetic supracondylar nonunions or those with acute fractures with bone stock inadequate for internal fixation are reasonable candidates for megaprostheses. Davila et al.55 have reported a small series of supracondylar distal femoral nonunions treated with a megaprostheses in elderly patients. They have shown that a cemented megaprosthesis in this patient population permits early ambulation and return to activities of daily living. Freedman83 performed distal femoral replacement in five elderly patients with acute fractures and reported four good results and one poor result secondary to infection. The four patients with good results regained ambulation in less than 1 month and had an average arc of motion of 99 degrees. All patients had some degree of extension lag. 
For a younger, active patient, an allograft-prosthetic composite may be a better alternative. Distal femoral reconstruction with an allograft-prosthetic composite, providing a biologic interface, can help restore bone stock and potentially make future revision easier.45,71 Kraay et al.142 have reported a series of allograft-prosthetic reconstructions for the treatment of supracondylar fractures in patients with TKAs. At a minimum 2-year follow-up, the mean Knee Society Score was 71 and the mean arc of motion was 96 degrees. All femoral components were well fixed at follow-up. Results of this study indicate that large segmental distal femoral allograft-prosthetic composites can be a reasonable treatment method in this setting. 

Author’s Preferred Treatment of Periprosthetic Distal Femur Fractures

 
 

As with most periprosthetic fractures, the typical first branch of the decision tree is at the determination of the stability of the existing prosthesis (Fig. 23-29). When a distal femur fracture involves an associated loose prosthesis, revision arthroplasty is indicated. Because of the paucity of critical soft tissue attachments in this anatomic region, distal femoral replacement is our treatment of choice for these fractures. These prostheses provide adequate stability through their built-in constraint mechanisms and their insertion is technically straightforward for the surgeon practiced in this technique. They allow immediate weight bearing and therefore early rehabilitation, and they have reasonable outcomes. The longevity and complication rates associated with distal femoral replacement, however, do not favorably compare with fracture fixation of distal femoral fractures about stable implants.

 
Figure 23-29
Algorithm depicting the author’s preferred method of treatment for periprosthetic distal femur fractures.
Rockwood-ch023-image029.png
View Original | Slide (.ppt)
X
 

ORIF and IMN both are reasonable options for the management of distal femur fractures about stable and well-functioning femoral components. The decision for one or the other is based on fracture fragment size, the morphology of the femoral arthroplasty component, and surgeon’s preference. When the distal fracture fragment is so small that control of it with a retrograde nail is suspect, ORIF is indicated. We reserve IMN for cases where the distal fragment extends into the diaphyseal region but we recognize that it is reasonable to consider this option anytime the distal fragment is at least long enough to allow placement of two to three distal interlocks. Another absolute requirement for IM nailing is the presence of a prosthesis with an open intercondylar notch. Lateral locked plate fixation is our preferred method for any fracture confined to the distal metaphyseal region, even fractures that extend beyond the confines of the anterior flange of the femoral component. Our results of ORIF of extreme distal fractures are similar to results for more proximal fractures with larger distal fragments. However, in certain individual cases, we consider distal femoral replacement for these extreme distal fractures.

Periprosthetic Patella Fractures

A number of factors guide treatment of periprosthetic patella fractures. The integrity and tracking of the extensor mechanism, locations and displacement of the fracture, stability of the implant, and the available remaining bone stock must all be considered. As with management of other periprosthetic fractures, the determination of the optimal method can be complex and fracture management can be difficult. A clear vision of the ultimate management goals, typically restoration of the extensor mechanism and at least return to baseline function and pain levels, helps define the optimal individual management scheme. Treatment options include nonoperative management, ORIF, component resection, and patellectomy (partial or complete). 

Incidence, Risk Factors, and Prevention of Periprosthetic Patella Fractures

Patellar fracture is the second most frequent periprosthetic fracture around the knee joint, and given the critical nature of the extensor mechanism for knee function, these fractures are significant to the ultimate arthroplasty success. Fractures of the patella generally occur postoperatively and may occur with either an unresurfaced or a resurfaced patella.3,36,253 An analysis of fractures about TKAs from the Mayo Clinic joint registry published in 1999 indicated that postoperative fracture of the patella occurred in 0.7% of cases after primary TKA (n = 16,906) and 1.8% of cases after revision TKA (n = 2,904).16 The only intraoperative patella fractures occurred during revision TKA in 8 of 2,904 cases. These data should be interpreted with caution since they do not include postoperative fractures treated at institutions other than the Mayo Clinic and the duration of follow-up was not presented. Several other published series indicate that the frequency of periprosthetic patella fractures is up to 21% with revision TKAs.11,56,209,232,277 
Etiologic factors related to periprosthetic patella fractures may be either systemic or local. Systemic risk factors are not unique to these anatomic locations and are therefore similar to those for other types of periprosthetic fractures and primarily include osteopenia from a variety of causes. Patients with RA, especially those taking corticosteroids, are at a particularly high risk for fracture about a TKA.20,30,114 Chalidis et al.,36 in a literature review, found that only 11.68% of 539 reported fractures were directly associated with trauma. The remaining occurred spontaneously and most fractures occurred during the first 2 years after arthroplasty. Etiologic factors specific to the patella are component design, excessive resection of bone, limb and prosthesis alignment, and presence or absence of a lateral release.26,31,75,92,110,232 Intraoperative fractures, although very uncommon, can occur with aggressive clamping of the patellar component, bone resection leaving less than 10 to 15 mm of bone, in the setting of revision arthroplasty, and in cases with poor remaining bone stock. Devascularization of the patella from lateral retinacular release may be a risk factor for subsequent fracture as well as for failure of subsequent fracture management. Tria et al.277 reported that all 18 patella fractures in a series of 504 primary TKAs were associated with a prior lateral release. In this series, 4% of those with lateral release (n = 413) had subsequent fracture of the patella compared to 0% of those without lateral release (n = 91). The association of lateral release and fracture was significant. However, opposite results were found in another study by Ritter and Campbell.232 In this series, the vast majority of the 555 patients did not have a lateral release (n = 471). Fractures occurred in 1.2% of cases with and 3.6% of those without lateral release. These conflicting reports, both from large series, make it difficult to determine if lateral release should be considered an independent risk factor for patella fracture. Any prior bony defects, such as from bone-patellar tendon-bone donor sites used for ligament reconstructions are additional potential risk factors for fracture of the patella. 

Classification of Periprosthetic Patella Fractures

There are many classification schemes utilized for periprosthetic patella fractures.92,119,205 In an extensive literature review, Chalidis et al.,36 found that the classification scheme of Ortiguera and Berry205 was utilized most frequently in the available literature. This classification takes into account the integrity of the extensor mechanism, the status of the patellar component (well fixed or loose), and the amount of available bone stock (Table 23-24). Type I fractures have an intact extensor mechanism and a stable implant, type II have disruption of the extensor mechanism with or without a stable implant, and type III have an intact extensor mechanism and a loose implant. Type III subtype A has reasonable remaining bone stock, and subtype B has poor bone stock. Among 265 fractures in the literature classified using this system approximately 50% were type III with the rest almost equally divided between types I and II.36 
Table 23-24
Ortiguera and Berry Classification for Periprosthetic Patella Fractures205
Classification Type I Type II Type IIIa Type IIIb
Extensor Mechanism Intact Disrupted Intact Intact
Implant Fixation Well fixed Well fixed or Loose Loose Loose
Bone Stock Unspecified Unspecified Reasonable Poor
X

Management of Periprosthetic Patella Fractures

Nonoperative management is usually appropriate in a majority of patients with periprosthetic patella fractures. When the extensor mechanism is intact and even sometimes when it is not, nonoperative management is recommended. Surgical management of periprosthetic patella fractures is usually reserved for disturbance of the extensor mechanism integrity, a loose patellar component, and patellar maltracking. 
When there is adequate bone stock (more than 10 mm), revision of the patellar component is reasonable. Avulsion fractures of the proximal or distal pole are amenable to suture repair. Severe bone deficiency, however, usually mandates patellar resection arthroplasty with partial or complete patellectomy. A novel reconstructive technique for management of type IIIB fractures, those with bone loss and a loose component, has recently been reported.7 Multiple Steinmann pins are used to reduce and stabilize the patella and act as a scaffold for bone grafting and a patellar button is cemented into the construct. 

Outcomes for Periprosthetic Patella Fractures

The results of surgical management of periprosthetic patella fractures are marginal. ORIF with tension band technique or cerclage wiring results in nonunion (Fig. 23-30) in a very large proportion of patients in many reports, with an overall average nonunion rate of 92%.26,36,43,93,119,132,205,251 Although fibrous union can, on occasion, restore painless extensor mechanism function, poor results in the face of nonunion can be expected. The relatively small and avascular fracture fragments have limited healing potential which can be negatively influenced by surgical dissection potentially leading to nonunion and infection. Therefore, nonoperative management is not an unreasonable consideration even in the face of a disrupted extensor mechanism. The presence of fracture and a loose implant is understandably associated with high complication rates regardless of treatment method. These situations usually lead to surgery for either removal or revision of the component. 
Figure 23-30
An acute periprosthetic patella fracture (A, B) treated with a K-wire and suture tension band results in secondary displacement and nonunion (C, D).
Rockwood-ch023-image030a.png
View Original | Slide (.ppt)
Rockwood-ch023-image030b.png
View Original | Slide (.ppt)
X
Knee function among all patients treated for periprosthetic patella fracture reveals an extensor lag of no more than 10 degrees and a limitation of approximately 20 to 30 degrees of flexion in most patients.36 However, function is highly variable and related to the ultimate status of the extensor mechanism. 

Potential Pitfalls and Preventative Measures for Periprosthetic Patella Fractures

Too aggressive surgical indications of periprosthetic patella fractures are perhaps the greatest potential pitfall. These fractures have high complication rates associated with surgical management. Nonsurgical management should therefore at least be strongly considered for nearly all of these fractures. 

Author’s Preferred Treatment of Periprosthetic Patella Fractures

 
 

Patella fractures are among the most difficult periprosthetic fractures to manage (Fig. 23-31). Operative management is associated with relatively high nonunion and infection rates and nonoperative management may require prolonged immobilization and does not address loose components. We tend to lean toward nonoperative management for these fractures unless displacement is severe or the component is so loose that it may dislodge. A staged management protocol that treats a periprosthetic patella fracture associated with a loose component sequentially rather than simultaneously is sometimes prudent to avoid major complications. Nonoperative fracture management to healing followed by surgical management of a loose component, if symptomatic, is a strategy that takes longer to complete but may ultimately result in fewer complications. When acute operative management is undertaken in the face of a stable component, we have a low threshold for excision of small- to moderate-sized superior or inferior pole fragments with suture repair of the associated tendon to the remaining bone. Patellectomy is our operative treatment of choice for cases with a loose prosthesis and poor bone stock.

Figure 23-31
Algorithm depicting the author’s preferred method of treatment for periprosthetic patella fractures.
Rockwood-ch023-image031.png
View Original | Slide (.ppt)
X

Periprosthetic Proximal Tibia Fractures

Incidence, Risk Factors, and Prevention of Periprosthetic Proximal Tibia Fractures

Tibia Fractures About Total Knee Components

Periprosthetic tibia fractures about TKA are uncommon. An analysis of fractures about TKAs from the Mayo Clinic Joint Registry published in 1999 indicated that postoperative tibia fracture occurred in 0.4% of cases after primary TKA and 0.9% of cases after revision TKA.16 Intraoperative fractures, in this series, were found to occur in 0.67% of primary and 0.8% of revision TKAs. These data should be interpreted with caution because they do not include postoperative fractures treated at institutions other than the Mayo Clinic and the duration of follow-up was not presented. In a more recent report of 17,389 primary TKAs performed between 1985 and 2005, intraoperative tibia fracture was found to be much less common than the Mayo experience: fracture occurred in 18 of the 17,389 cases (0.1%).3 
Nonspecific etiologic factors related to periprosthetic tibia fractures are similar to those described in the prior section regarding periprosthetic patella fractures and include poor bone quality. BMD in the tibia below the tibial component has been shown to progressively decrease at 3 years follow-up after arthroplasty.215,289 
Local risk factors for periprosthetic tibia fractures may be related to technique as well as to implant design. The largest series of periprosthetic tibial fractures around loose prostheses was reported by Rand and Coventry.223 They reported that all 15 knees had varus axial malalignment when compared to a control group. Similar studies have confirmed that varus malalignment may be a potential risk factor for periprosthetic tibial fracture.170,293 Osteotomy of the tibial tubercle facilitates exposure for the very stiff knee but it reduces the structural integrity of the proximal tibia. In a small series of nine TKAs with tibial tubercle osteotomy, Ritter et al.233 reported two proximal tibia fractures. Both cases occurred soon after surgery (within 2 months) and each healed with nonoperative management. Any prior bony defects, such as from patellar tendon donor sites or tunnels associated with anterior cruciate ligament reconstructions, are additional risk factors for fracture of the tibia. Prior fracture malunion and holes from prior fixation devices for high tibial osteotomy or tibial plateau fracture fixation pose stress risers and are also potential sites for fracture. 
Fracture associated with uncemented insertion of the low-contact stress (LCS) knee system tibial component has been reported.274 The technique used for implantation of this prosthesis, reaming a conical hole for the tibial stem without impaction and absence of trialing, rather than the implant itself may have been causative. 

Tibia Fractures About Unicompartmental Components

A small number of tibia fractures associated with unicompartmental knee arthroplasty have been reported including both intraoperative and postoperative fractures.146,239,284 Suggested risk factors include broaching the posterior cortex during preparation of the tibia,257 using multiple guide pinholes in the proximal tibia,27 an extended vertical saw cut,239 improper component positioning, malalignment, loosening,74 and obesity.239 A biomechanical study indicates that extending the vertical cut posteriorly by increasing the sagittal plane cut angle caudally by just 10 degrees reduces fracture load by 30%.44 

Classification of Periprosthetic Proximal Tibia Fracture

Location of the fracture, stability of the implant, and timing of the fracture (intra- or postoperative) are incorporated into the classification of periprosthetic tibia fractures according to Felix et al.74,266 Type I fractures occur in the tibial plateau. Postoperative fractures of this type were thought to be stress fractures related to loosening or malalignment of the component. These were a common fracture type prior to introduction of keeled components. Type II fractures are adjacent to the stem tip and are generally related to trauma in the setting of osteolysis. Type III fractures are distal to the prosthesis, and Type IV involve the tibial tubercle. Subtype A has a well-fixed implant, subtype B has a loose implant, and subtype C occur intraoperatively (Table 23-25) (Fig. 23-32). 
Figure 23-32
 
Classification scheme for periprosthetic tibia fractures about a TKA: Type I fractures involve only a small portion of the tibial plateau; type II fractures are about the stem; type III fractures are distal to the stem; and Type IV fractures are of the tibial tubercle. The subtypes are described in Table 25.
Classification scheme for periprosthetic tibia fractures about a TKA: Type I fractures involve only a small portion of the tibial plateau; type II fractures are about the stem; type III fractures are distal to the stem; and Type IV fractures are of the tibial tubercle. The subtypes are described in Table 25.
View Original | Slide (.ppt)
Figure 23-32
Classification scheme for periprosthetic tibia fractures about a TKA: Type I fractures involve only a small portion of the tibial plateau; type II fractures are about the stem; type III fractures are distal to the stem; and Type IV fractures are of the tibial tubercle. The subtypes are described in Table 25.
Classification scheme for periprosthetic tibia fractures about a TKA: Type I fractures involve only a small portion of the tibial plateau; type II fractures are about the stem; type III fractures are distal to the stem; and Type IV fractures are of the tibial tubercle. The subtypes are described in Table 25.
View Original | Slide (.ppt)
X
 
Table 23-25
Classification for Periprosthetic Tibia Fractures
View Large
Table 23-25
Classification for Periprosthetic Tibia Fractures
Classification Type I Type II Type III Type IV
Fracture Location Tibial plateau Adjacent to stem Distal to prosthesis Tibial tubercle
Subtype
A Prosthesis well fixed Prosthesis well fixed Prosthesis well fixed Prosthesis well fixed
B Prosthesis loose Prosthesis loose Prosthesis loose Prosthesis loose
C Intraoperative Intraoperative Intraoperative Intraoperative
X

Management of Periprosthetic Proximal Tibia Fractures

Management of Tibia Fractures About Total Knee Components

On the occasion where periprosthetic tibia fracture is associated with a well-fixed component, nonoperative management with a cast or brace is indicated for nondisplaced fractures. If cast management is chosen, great care should be taken to monitor for pressure sores especially in patients with RA and those with diabetes. Maintenance of limb alignment is important; therefore, frequent, usually weekly, radiographic surveillance is advisable with conversion to ORIF for failure to maintain satisfactory alignment. As with any other immobilized joint, arthrofibrosis is a potential risk factor. 
ORIF is indicated for displaced periprosthetic proximal tibia fractures associated with a well-fixed component. ORIF is advisable for displaced fractures involving the metaphyseal–diaphyseal junction (Fig. 23-33). Plate and screw constructs are limited by the available bone proximally to pass bicortical screws. This is highly dependent upon the prosthesis design with regard to the degree of metaphyseal filling. The inability to pass multiple screws across the proximal fragment can lead to insufficient fixation and calls for adjunctive fixation with unicortical locked screws, cables, secondary posterior-medial plates, or some combination thereof (Fig. 23-34). This scenario is common, so the surgeon should be prepared to deal with marginal fixation in the proximal fragment afforded by a lateral plate and screw construct. A medial plate usually adds sufficient stability even when a limited number of proximal fixation points are obtained. 
Figure 23-33
A periprosthetic proximal tibia fracture (A, B) treated with a lateral proximal tibia locking plate that is supplemented with a posterior lateral plate (C, D).
Rockwood-ch023-image033a.png
View Original | Slide (.ppt)
Rockwood-ch023-image033b.png
View Original | Slide (.ppt)
X
Figure 23-34
 
A periprosthetic proximal tibial fracture treated with a single medial plate that offered marginal fixation progresses to nonunion (A) that is treated successfully with a combination of lateral locked plating, posterior-medial locked plating, bone grafting, and adjuvant BMP (B).
A periprosthetic proximal tibial fracture treated with a single medial plate that offered marginal fixation progresses to nonunion (A) that is treated successfully with a combination of lateral locked plating, posterior-medial locked plating, bone grafting, and adjuvant BMP (B).
View Original | Slide (.ppt)
Figure 23-34
A periprosthetic proximal tibial fracture treated with a single medial plate that offered marginal fixation progresses to nonunion (A) that is treated successfully with a combination of lateral locked plating, posterior-medial locked plating, bone grafting, and adjuvant BMP (B).
A periprosthetic proximal tibial fracture treated with a single medial plate that offered marginal fixation progresses to nonunion (A) that is treated successfully with a combination of lateral locked plating, posterior-medial locked plating, bone grafting, and adjuvant BMP (B).
View Original | Slide (.ppt)
X
Fractures in the midtibial shaft, distal to a tibial component, are typically treated with ORIF, especially when associated with stemmed components (Fig. 23-35). When a nonstemmed THA component is present, IMN of tibial shaft fractures can be successfully performed (Fig. 23-36). Care must be taken to assure there is adequate space for the nail anterior to the tibial component so that the tibial tubercle is not disturbed (Fig. 23-36C). 
Figure 23-35
This was managed with a lateral plate and an anterior medial strut allograft.
View Original | Slide (.ppt)
Figure 23-35
A fracture about a well-fixed stemmed tibial component of a TKA had a previously untreated perforation near the tip of the stem.
This was managed with a lateral plate and an anterior medial strut allograft.
This was managed with a lateral plate and an anterior medial strut allograft.
View Original | Slide (.ppt)
X
Figure 23-36
A tibial shaft fracture below a nonstemmed TKA (A) is treated with an IM nail (B).
 
Note that there must be sufficient space between the tibial component and the nail (C) to allow insertion without disturbing the tibial tubercle.
Note that there must be sufficient space between the tibial component and the nail (C) to allow insertion without disturbing the tibial tubercle.
View Original | Slide (.ppt)
Figure 23-36
A tibial shaft fracture below a nonstemmed TKA (A) is treated with an IM nail (B).
Note that there must be sufficient space between the tibial component and the nail (C) to allow insertion without disturbing the tibial tubercle.
Note that there must be sufficient space between the tibial component and the nail (C) to allow insertion without disturbing the tibial tubercle.
View Original | Slide (.ppt)
X
Tibial fractures associated with loose components are best treated with revision arthroplasty, frequently utilizing a long stem to bypass the fracture.11,71,74 It is wise to have an entire revision system available, because, often the femoral component will need to be revised as well for sizing, constraint, exposure, or gap balancing reasons. Often these fractures are associated with extensive osteolysis and therefore may require structural or morselized bone grafting, the use of metal wedges, or in the most severe cases proximal tibial megaprosthesis or allograft-prosthetic composites. Maximizing host bone support is critical for a good result. General principles for arthroplasty treatment of periprosthetic tibia fractures include the use of stem extensions with either metaphyseal cementation or longer, diaphyseal press-fit strategies. More contemporary techniques utilize metaphyseal-filling sleeves that provide rotational and axial stability, however, long-term data on such reconstructions is lacking. 
Specific technical considerations include careful soft tissue dissection and retraction to minimize soft tissue trauma to the already compromised skin flaps. The anteromedial capsule is a major source of wound-healing problems or postoperative drainage. If there is a deficiency in this area that cannot be approximated well, a gastrocnemius flap may be indicated. The extensor mechanism and its insertion along the proximal tibia is a crucial consideration. The tibial tuberosity can be osteotomized and repaired for exposure or repaired directly to the implant for proximal tibial replacement prosthesis. It is important that the surgeon undertaking these reconstructions be experienced in both revision arthroplasty techniques and fracture management techniques to achieve a successful outcome. 

Management of Tibia Fractures About Unicompartmental Components

Tibia fractures about unicompartmental knee arthroplasties can be managed in a variety of ways including with nonoperative means,14 ORIF,239,257 and revision to TKA.27,167,284 There is very little literature available at this point to guide decision making, therefore general principles of periprosthetic fracture management must be relied upon. Under usual circumstances, stable fractures with stable components can be managed nonoperatively,14 unstable fractures with stable components can be managed with ORIF,239,257 and any fracture associated with an unstable component would demand revision arthroplasty,27,167,284 typically revision to a TKA. As with native medial tibial plateau fractures, nondisplaced periprosthetic fractures of the medial plateau about a unicompartmental component have a propensity to displace over time. Therefore careful observation is warranted and changes in fracture alignment should prompt consideration of operative management as progressive displacement of these fractures is common. 

Outcomes for Periprosthetic Proximal Tibia Fractures

There is exceedingly little published literature regarding outcomes after periprosthetic proximal tibia fracture after TKA. Felix et al.,74 in 1997, reported on a large series of 102 fractures. The majority of types I and II fractures were associated with loose prostheses and were treated successfully with revision arthroplasty. Fractures associated with well-fixed components were managed with the usual principles of tibia fracture management of that time period. 
Several case reports demonstrate isolated results for various methods of treating tibia fractures about unicompartmental knee arthroplasties but few describe much detail or long-term outcomes. Berger et al.14 presented results of 38 patients followed for 10 years after unicompartmental knee arthroplasty. Three patients had tibial plateau fractures, two noted intraoperatively and one that occurred intraoperatively, but was not recognized until the first postoperative visit. All were treated nonoperatively, healed, and had a good ultimate outcome. Rudol et al.239 described a postoperative, and Sloper et al.257 an intraoperative, vertical medial tibial plateau fracture, each treated successfully with buttress plating.239 Pandit et al.208 described eight fractures about a unicompartmental knee arthroplasty treated in a variety of ways resulting in a variety of outcomes. Two minimally displaced fractures were treated nonoperatively, healed, and had good outcomes with retained unicompartmental components at either 1 or 3 years. Three others failed nonoperative management and ultimately required conversion to TKA. Two of these three also failed intermediate surgical management of their nonunited fractures, but all three had good outcomes at between 1 and 4 years. Two others had occult fractures that upon initial diagnosis had already subsided and these two patients were managed with conversion to TKA and were with good results at 2 years. The eighth patient in the series was treated to union with a buttress plate and had a good result at 2 years. Van Loon et al.284 reported three cases where revision to TKA was performed either immediately after intraoperative fracture (n = 1), after initial ORIF (n = 1), or after nonoperative management (n = 1). The precise indications for conversion to TKA were not identified in this report, but were related to pain and reduced mobility in the latter two cases. Follow-up was 2 years or less and results at this short follow-up were mixed. 

Potential Pitfalls and Preventative Measures for Management of Periprosthetic Proximal Tibia Fractures

Obtaining adequate fixation during ORIF of periprosthetic proximal tibia fractures can be a challenge (Table 23-26). The tibial component often fills a substantial volume of the proximal tibial metaphysis, making placement of bicortical screws difficult or impossible. Dual plating of these fractures is often required to obtain adequate fracture stability. Care must be taken to maintain adequate skin bridges between medial and lateral incisions used for ORIF and any anterior incision pre-existing from the knee arthroplasty. The medial incision can be placed sufficiently posterior to minimize risk of skin necrosis while still allowing adequate exposure for posterior-medial plating. Despite the potential risk for skin necrosis, using multiple incisions is still preferred to extensive deep dissection through fewer incisions. 
 
Table 23-26
Periprosthetic Proximal Tibia Fractures
View Large
Table 23-26
Periprosthetic Proximal Tibia Fractures
Potential Pitfalls and Preventions
Pitfalls Preventions
Loss of proximal fixation after ORIF Medial and lateral locked plates
Maximize number of locked screws in proximal fragment
Skin necrosis Maintain adequate skin bridge between incisions
Devitalization of bone Minimize soft tissue stripping from bone
Use multiple incisions
X

Author’s Preferred Treatment of Periprosthetic Tibia Fractures

 
 

Fortunately, periprosthetic tibia fractures around TKAs are relatively uncommon (Fig. 23-37). When they do occur, most often they are associated with a loose tibial component; therefore revision is preferred in these situations. Tibial revision for periprosthetic fracture requires the routine use of stems and augments and metaphyseal-filling metal implants can be useful for managing bone deficiencies. The tibial base trays have often subsided into varus, and anticipating medial and central defects is wise. The surgeon should be aware that isolated tibial component revision is rare, and commonly, one should be prepared to revise the entire arthroplasty.

 
Figure 23-37
Algorithm depicting the author’s preferred method of treatment for periprosthetic proximal tibia fractures.
Rockwood-ch023-image037.png
View Original | Slide (.ppt)
X
 

When the tibial component is stable and the fracture displaced, our preferred method of treatment is with lateral locked plates. Although there is scant literature supporting this or any other practice for these fractures, it is our feeling that locked plates are invaluable for these fractures. The amount and quality of bone proximally is usually marginal and in these situations nonlocked screws rarely obtain adequate fixation. Locked screws proximally and either locked or nonlocked screws distally through a lateral plate may provide sufficient stability. We, however, have a low threshold to supplement a lateral plate with a posterior-medial locked plate (Figs. 23-33 and 23-34). Medial comminution and an inability to pass lateral screws across to the medial side are indications for dual plating. It is critical that these exposures be through separate incisions so as to maximally preserve the soft tissue envelope. Even in the presence of a midline incision from the TKA, separate lateral and medial incisions can provide an adequate skin bridge in all but the thinnest of patients.

Periprosthetic Fractures about Ankle Arthroplasty

Incidence, Risk Factors, and Prevention of Periprosthetic Fractures About Ankle Arthroplasty

There have been a number of reports of malleolar fractures complicating total ankle arthroplasty (TAA), but no large series have been published to date clearly elucidating specific etiologic factors or classification schemes.108,152,181,197,242,248,295 One risk factor, however, seems to be clear. Multiple studies have demonstrated that intraoperative fractures of the malleoli decrease with increasing surgeon experience with the procedure. Lee et al.152 and Myerson and Mroczek197 each compared results of their first 25 TAA cases to their next 25. Both showed substantial reduction in intraoperative malleolar fractures with experience: Lee had four fractures among the first 25 cases (16%) and one in the subsequent 25 (4%), and Myerson had five from the initial group (20%) and two from the second group (8%). These results are similar to those of several other authors. Haskell and Mann108 found a reduction in intraoperative fracture from 12% in the initial 50 cases to 9% in the subsequent 137 cases, and Schuberth et al.248 reported 19 intraoperative fractures from 50 cases (38%) and noted that this complication decreased with experience. 
The medial malleolus is the most common site of intraoperative fracture, occurring approximately twice as frequently as lateral malleolus fracture.63,108,181,242,295 In a series of 93 TAAs performed for inflammatory joint disease, there were 27 intraoperative fractures: 15 of the medial malleolus, 7 of the anterolateral distal tibia, and 5 of the lateral malleolus.63 
Although the vast majority of periprosthetic fractures about TAAs occur intraoperatively (Fig. 23-38), postoperative malleolar fracture has been reported.63,100,108,181,295 Wood and Deakin295 had 10 postoperative fractures occurring between 3 days and 23 months postoperatively in their series of 200 TAAs. Two of the 10 were associated with implant loosening. Doets et al.63 reported four fractures occurring between 4 and 6 months postoperatively in a series of 93 TAAs performed in patients with inflammatory joint disease. Severe osteopenia was noted in all four patients with postoperative fractures. 
Figure 23-38
An intraoperative lateral malleolus fracture related to inadvertent saw cut of the lateral malleolus (A) heals with screw fixation (B).
Rockwood-ch023-image038.png
View Original | Slide (.ppt)
X

Management and Outcomes of Periprosthetic Fractures About Ankle Arthroplasty

There are no accepted standards for treatment of periprosthetic fractures about TAA. However, the general principles of management of other periprosthetic fractures can be applied. Fracture union, implant stability, and re-establishment of any associated loss of bone stock are general goals of management with the hope of restoring baseline function. Several authors describe internal fixation for intraoperative malleolar fractures that compromised implant stability108,181 and yet others treated many of these fractures nonoperatively.152,197,295 Nonunion occurred after intraoperative fracture in one of six nonoperatively treated from one study108 and in one of five treated with ORIF from another.181 Either screw fixation or cast immobilization was used for treatment of 27 intraoperative fractures in the series of Doets et al.63 Six of 15 with medial malleolar fractures, one of seven with anterolateral distal tibia fractures, and two of five with lateral malleolar fractures were treated with screw fixation. Among these patients, two with medial malleolar fractures were ultimately considered failures. 
Most postoperative fractures are also of the malleolus and are typically treated nonoperatively unless associated with implant loosening or osteolysis.108,181,295 A very small number of displaced postoperative fractures of the distal tibia metaphysis associated with TAA, six to the best of our knowledge, have been reported.63,100,301 Each was associated with a stemmed tibial component. Treatment with either an anterolateral or medial locked plate in two cases that were associated with trauma mimicked standard treatment of a native extra-articular distal tibia fracture.100,301 

Author’s Preferred Treatment of Periprosthetic Fractures about Ankle Arthroplasty

 
 

Periprosthetic ankle fractures are uncommonly dealt with, except by those surgeons who perform a high volume of TAAs, especially since the majority of these fractures occur intraoperatively (Fig. 23-39). When an intraoperative fracture is encountered, ORIF is preferred, except for the most minimally displaced fracture, to maximize stability of the arthroplasty. Postoperative fractures about stable implants are treated operatively with ORIF when the fracture potentially affects joint stability or when displacement is great enough to risk nonunion with nonoperative treatment.

Figure 23-39
Algorithm depicting the author’s preferred method of treatment for periprosthetic fractures about a total ankle arthroplasty.
Rockwood-ch023-image039.png
View Original | Slide (.ppt)
X

Periprosthetic Fractures about Shoulder Arthroplasty

Incidence, Risk Factors, and Prevention of Periprosthetic Fractures About Shoulder Arthroplasty

Humeral Shaft Fractures About Stemmed Shoulder Arthroplasty Components

Fractures of the humerus associated with total shoulder arthroplasty (TSA) or hemiarthroplasty occur with intermediate frequency relative to other periprosthetic fractures. Among series that focus exclusively on fractures that occurred postoperatively, the incidence has been remarkably consistent at between 0.6% and 2.3%.23,147,296,297 With only limited data to rely on, the incidence of intraoperative fracture may be substantially higher. Two studies that distinguish between intraoperative and postoperative fractures both found two times more fractures occurred intraoperatively.32,95 A recent study focusing on intraoperative fractures found the rate of humeral fracture after primary shoulder arthroplasty to be 1.7% and the rate during revision arthroplasty to be 3.3%.10 Of the 45 fractures in this report, 19 were of the greater tuberosity, 16 of the humeral shaft, 6 of the metaphysis, 3 of the greater tuberosity with shaft extension, and one that included the greater and lesser tuberosities. 
Many risk factors for fracture have been postulated, but the limited number of fractures in most series, usually less than 10, makes scientific analysis impossible. It is logical, however, that conditions that further weaken a bone that already has a stress riser would put that patient at a particularly high risk of fracture after even minor trauma. 
RA has been implicated as a significant risk factor. In Boyd’s series of seven postoperative fractures, five patients had RA. The incidence of fracture among those treated with their initial arthroplasty because of RA (1.8%), however, was only slightly higher than for those treated for other diagnoses (1.5%). Studies from the Mayo Clinic, where a large proportion of patients had a primary diagnosis of RA have shown higher incidences of fracture among patients with RA. Wright and Cofield.297 reported on nine postoperative fractures from a cohort of 499, 144 of whom had RA. The incidence of fracture was 3.4% among those with RA and 1.1% among the rest. A more recent study from the Mayo Clinic that included a larger cohort of patients found a relatively low overall incidence of postoperative fracture of 0.6%, 19 fractures among 3,091 patients.147 The proportion of fractures that occurred in patients with RA was high (31%) but the relative numbers of patients in the entire cohort who had RA were not reported, so evaluation of RA as a risk factor is not possible. 
Osteopenia or severe cortical thinning has been cited as a risk factor for periprosthetic humeral fracture, especially among patients with revision arthroplasty stems.32,95,261 Is should be noted, however, that such statements have been made with indirect data regarding the degree of osteopenia in some series.32,95 Campbell et al.32 quantified the degree of osteopenia as the ratio of the combined width of the mid-diaphyseal cortices to the diameter of the diaphysis. Normal bone was considered to have a ratio of greater than 50%, mild osteopenia had a ratio of between 25% and 50%, and severe osteopenia less than 25%. Although the validity of these criteria and definitions is unsubstantiated, Campbell et al. found 25% of 20 patients with a fracture had normal bone, 45% mild osteopenia, and 30% severe osteopenia. It is useful to note that their 75% prevalence of osteopenia in this cohort is very high; however, without data on the bone quality of those without fracture, it is inaccurate to conclude that this truly represents a risk factor for fracture. Kumar et al.147 also utilized this system to grade bone quality and found all of their patients with fracture had osteopenia (44% severe). The presence or degree of osteopenia has not been correlated with a particular injury mechanism or a particular treatment strategy. It seems intuitive, however, that any treatment algorithm in a patient with severely compromised bone stock should include consideration of minimizing the presence of stress risers in the final fracture treatment construct to avoid subsequent additional fractures. 
Other implicated risk factors for postoperative fracture, advanced age and female gender,180 are also limited by a lack of data for patients without fracture. When such data is available, age does not appear to be substantially different in those with and without fracture. The average age of all 3,091 patients who had undergone shoulder arthroplasty at the Mayo Clinic between 1976 and 2001 was 63 years and the age of those who sustained a fracture was also 63 years.147 The female-to-male ratio was slightly higher in those with fracture (63%) compared to the entire group (56%). 
A number of technical issues may relate to intraoperative fracture. Most of these relate to manipulations of the humerus during surgical exposure or to preparation of the canal with reamers or an oversized broach.32,95 Excessive external rotation required to provide exposure in patients with large muscles or scars was causative for half of all intraoperative fractures in one series.32 In half of the cases with fracture associated with external rotation, over reaming of the diaphysis caused notching of the endosteum resulting in a stress riser for spiral fracture formation during subsequent external rotation. Hoop stresses associated with an oversized broach or prosthesis can cause transverse or oblique fractures.32,95 Fracture during revision shoulder arthroplasty may be intentional32 as the least destructive method to remove a stem. Unintentional fracture may also occur during explantation of the prosthesis, removal of associated cement, or during implantation of the revision prosthesis. 
Treatment of periprosthetic humeral shaft fractures, as much as any other periprosthetic fracture, starts with prevention of intraoperative fracture. Steps include detailed preoperative planning particularly with regard to templating stem diameter. This requires good quality preoperative radiographs taking into account magnification. Substantive soft tissue releases reduce risk of fracture by reducing stresses that accompany arm manipulations during arthroplasty. Capsular contractures as well as scar formations in the subacromial and subdeltoid spaces should be addressed to allow gentle delivery of the bone so stress-free preparation and implantation can occur. Proper sizing of the implant and meticulous care to be colinear with the long axis of the bone during canal preparation will help to avoid perforation. Small perforations that are diagnosed intraoperatively can easily be treated with a stem that bypasses the defect by two or more bone diameters. There should be a low threshold for intraoperative radiographs to assure a split that propagated distally did not accompany the perforation, as this might require additional treatment to stabilize the distal extent of such a fracture. 

Humeral Fracture About Resurfacing Shoulder Arthroplasty Components

Periprosthetic fracture of the humerus after resurfacing has been reported infrequently.126,273 One case occurred intraoperatively and was managed successfully without operation.273 Another reported case occurred postoperatively secondary to a fall and resulted in a surgical neck fracture. Initial nonoperative management was abandoned in favor of ORIF with a locked plate because of progressive displacement.126 These authors point out that the specific design of the resurfacing implant may dictate treatment. The Epoca prosthesis involved in their case is a shell-like design that allowed screws to penetrate the head fragment. Other resurfacing designs would make screw placement more challenging and would therefore make revision to a stemmed humeral component more attractive. It is also unclear how the risk or consequence of avascular necrosis after ORIF of these fractures would affect outcome. 

Fractures About Reverse Shoulder Arthroplasty

Acromial fracture after a reverse TSA has been reported in several series.52,80,109,159 These fractures are generally atraumatic and are associated with stress on the deltoid origin and are therefore often nondisplaced or minimally displaced. They occur relatively commonly, with a prevalence of up to 10%,52,80,159 but can be missed on plain radiographs159 and therefore may be underreported. When suspected, based on pain or tenderness along the acromion or scapular spine, a CT scan is indicated when plain films are negative. 

Classification of Periprosthetic Fractures About Shoulder Arthroplasty

Classification of Periprosthetic Humeral Fractures About Shoulder Arthroplasty

Several classification schemes have been reported for periprosthetic humeral shaft fractures about shoulder arthroplasty stems. Most distinguish fractures by their location relative to the tip of the stem,32,95,297 and a smaller subset account for fractures of the tuberosities or the stability of the stem.296 None are universally accepted. Wright and Cofield297 described three fracture patterns occurring in their series of nine postoperative fractures, type A centered at the tip of the stem and extending proximally more than one-third the length of the stem, type B also centered at the tip of the stem but with less proximal extension, and type C involved the distal humeral diaphysis, distal to the tip of the stem, extending into the metaphysis. Campbell et al.32 categorized fractures into one of four regions. Region 1 included the greater or lesser tuberosities, region 2 the proximal metaphysis, region 3 the proximal humeral diaphysis, and region 4 the mid- and distal diaphysis. They classified their 21 fractures based on the distal most fracture extent. Groh et al.,95 like Wright and Cofield, classified fractures of the shaft into three types. Type I occur proximal to the tip of the prosthesis, type II fractures originate proximal to the tip and extend distal to it, and type III fractures originate below the tip. Worland et al.296 considered each fracture location, fracture obliquity, and implant stability. They also made treatment recommendations based on the fracture classification. Types A, B, and C were designated by the location of the fracture: A about the tuberosities, B around the stem, and C well distal to the stem. Type B fractures were subdivided: B1 fractures were spiral with a stable stem; B2 were transverse or short oblique with a stable stem; and B3 were any fracture associated with a loose stem. Their recommended treatment was very general, with conservative management or ORIF recommended for all but B2 and B3 types where long stem revision was recommended. 

Classification of Scapular Fracture About Shoulder Arthroplasty

Two classification systems have been reported for periprosthetic acromial fractures associated with reverse shoulder arthroplasty.52,159 Levy et al.159 described type I acromial fractures as distal and involving the anterior and middle deltoid origin, type II fractures as being of the central portion of the acromion and involving at least the entire middle deltoid origin, and type III fractures being of the base of the acromion and involving the entire middle and posterior deltoid origin. This classification scheme was based on evaluation of 16 fractures. Five of these fractures were not evident on plain radiographs and required CT for diagnosis. The interobserver reliability was found to be excellent. 
Because of the relative rarity of periprosthetic fractures about glenoid components and an absence of large series dealing with them, no generally accepted fracture classification exists for these fractures. 

Management of Periprosthetic Fractures About Shoulder Arthroplasty

Management of Intraoperative Periprosthetic Tuberosity Fractures

Nondisplaced or minimally displaced fractures of the lesser tuberosity can occur with some frequency during placement of the trial humeral component. Treatment of these is generally with suture repair using heavy nonabsorbable sutures placed through the subscapularis tendon and either through or around the lesser tuberosity then into the adjacent intact bone on the other side of the fracture. Similarly, cracks about the greater tuberosity are stabilized with sutures to assure displacement does not ensue. 

Management of Periprosthetic Humeral Shaft Fractures

Humeral shaft fractures are treated with goals of uneventful fracture healing and implant stability (Table 23-27).57,261 This can be accomplished by a variety of means. Intraoperative fractures of the shaft are carefully examined with intraoperative radiographs. A long-stemmed noncemented prosthesis with adjunctive cerclage cables is useful for spiral fractures. More transverse intraoperative fractures that are not amenable to cable stabilization are more appropriately treated with a long-stemmed prosthesis and either plate or strut stabilization. As with other diaphyseal periprosthetic fractures, when there is compromised bone stock, strut allografts are utilized. 
Table 23-27
ORIF for Periprosthetic Humeral Shaft Fractures About Shoulder Arthroplasty
Surgical Steps
  •  
    Develop plane between long and lateral heads of triceps
  •  
    Identify radial neurovascular bundle
  •  
    Split triceps distally
  •  
    Dissect plane between radial neurovascular bundle and posterior humerus
    •  
      Debride fracture
  •  
    Reduce fracture and provisionally secure reduction with clamps, reduction plates, and/or cables
  •  
    Apply plate across fracture and beneath radial neurovascular bundle
    •  
      Secure plate proximally with cables and distally with screws
  •  
    Confirm reduction and implant location with radiographs
  •  
    Close triceps fascia
  •  
    Close skin
X
Fractures that occur postoperatively can be treated nonoperatively if the implant is stable and the fracture is otherwise amenable to bracing (Fig. 23-40). This usually means the fracture is middiaphyseal, spiral, or short oblique (not transverse), and there is no drastic displacement, where interposed muscle may inhibit fracture healing. A lower threshold for surgical management of periprosthetic humerus fractures compared to similar fractures of the native humerus may be justified. Whether the presence of the humeral component stem inhibits fracture healing is unproven, but it is reasonable to assume that instrumentation of the humeral canal may negatively affect the endosteal blood supply. However, the degree and duration of such an effect as well as the clinical significance remains unclear. Nonetheless surgical management, especially for transverse or short oblique fractures (Fig. 23-41), is commonplace. The preferred exposure is through a posterior approach. This is extensile and allows visualization of the entire shaft of the humerus. Furthermore, this exposure allows clear identification and protection of the radial nerve during reduction and plating, and most importantly during cable fixation in the zone of the prosthesis. Applying cables through an anterior exposure is dangerous with regard to potential injury and entrapment of the radial nerve. Consideration is given to the timing of the fracture relative to the arthroplasty. When the fracture occurs shortly after joint replacement, surgical fixation offers better capability to perform shoulder rehabilitation and therefore a low threshold exists to treat these fractures operatively. 
Figure 23-40
A humeral shaft fracture distal to a humeral prosthesis (A) treated nonoperatively to union (B).
Rockwood-ch023-image040.png
View Original | Slide (.ppt)
X
Figure 23-41
A periprosthetic humeral shaft fracture distal to a revision humeral component (A).
 
The proximal allograft was used previously during the revision arthroplasty. The acute periprosthetic fracture was treated via the posterior approach using biologic reduction techniques seen in an intraoperative photograph (B) that preserved the majority of the soft tissue attachments. A posterior plate with cables proximally and screws distally was used for fixation (C).
The proximal allograft was used previously during the revision arthroplasty. The acute periprosthetic fracture was treated via the posterior approach using biologic reduction techniques seen in an intraoperative photograph (B) that preserved the majority of the soft tissue attachments. A posterior plate with cables proximally and screws distally was used for fixation (C).
View Original | Slide (.ppt)
Figure 23-41
A periprosthetic humeral shaft fracture distal to a revision humeral component (A).
The proximal allograft was used previously during the revision arthroplasty. The acute periprosthetic fracture was treated via the posterior approach using biologic reduction techniques seen in an intraoperative photograph (B) that preserved the majority of the soft tissue attachments. A posterior plate with cables proximally and screws distally was used for fixation (C).
The proximal allograft was used previously during the revision arthroplasty. The acute periprosthetic fracture was treated via the posterior approach using biologic reduction techniques seen in an intraoperative photograph (B) that preserved the majority of the soft tissue attachments. A posterior plate with cables proximally and screws distally was used for fixation (C).
View Original | Slide (.ppt)
X
In the setting of a loose prosthesis with or without osteolysis, revision arthroplasty is indicated. A revision stem that crosses the fracture provides intramedullary stabilization and is usually accompanied by plate fixation in the absence of bone loss. Strut grafts (Fig. 23-42), with or without plates are used to restore any associated deficient bone stock. A noncemented technique is preferred whenever there is good quality bone to provide a reasonably tight fit. A low threshold for supplemental plate fixation is the norm. If either of the fragments has poor quality bone, a cemented technique can be utilized in that fragment (usually the distal fragment) and a noncemented technique in the other. When osteolysis is severe, either impaction bone grafting, an allograft–prosthesis composite, or a tumor prosthesis is utilized. These are extremely technically demanding cases that are individualized based on secondary factors and should be undertaken by surgeons and in centers familiar with and stocked with appropriate equipment, respectively. 
Figure 23-42
Treatment of a periprosthetic humeral shaft fracture associated with a loose prosthesis (A) with a long stem revision, allograft, and a cerclage cable (B).
Rockwood-ch023-image042.png
View Original | Slide (.ppt)
X

Management of Periprosthetic Glenoid Fractures

Periprosthetic fractures of the glenoid most commonly occur intraoperatively and are related to retraction. A retractor that is placed on the posterior glenoid margin to retract the humerus posteriorly during preparation of the glenoid articular surface can cause fracture. Patients undergoing revision surgery and those with severe osteopenia are at a particularly high risk. Large fragments may be treated with screws or plates. However, commonly, the fragments are small and comminuted and are not amenable to screw fixation. With inadequate bone support, glenoid resurfacing should be abandoned and the defect bone grafted. After fracture healing, conversion of the hemiarthroplasty to a TSA can be contemplated if symptoms require. 

Management of Periprosthetic Acromial Fractures About Reverse Shoulder Arthroplasty

Many fractures of the acromion about reverse shoulder arthroplasties are stress fractures.202 They are typically nondisplaced or minimally displaced and are usually amenable to nonoperative management with a sling or shoulder immobilizer and limited activity based on pain.159 Fracture healing is usually reliable and full activities can be resumed in 6 to 12 weeks. On the occasion of a displaced fracture, ORIF may be indicated.287 

Outcomes for Periprosthetic Fractures About Shoulder Arthroplasty

Outcomes of Periprosthetic Humeral Fractures About Shoulder Arthroplasty

The results of treating periprosthetic humeral shaft fractures about TSA nonoperatively are mixed in the literature and some advocate ORIF in this setting.21,23,32,95,134,147,180,261,296,297 Kumar et al.147 treated 11 postoperative periprosthetic humeral shaft fractures nonoperatively. Six healed uneventfully but five required eventual operative intervention, three had ORIF with bone grafting, and two underwent revision arthroplasty with a long stem for associated loosening. Failure of nonoperative management in this series may be related to the presence of loose implants. Immediate ORIF was performed in only two patients with stable prostheses; both had uneventful union. Similarly marginal results were reported by Boyd et al.23 in a small series where nonunion occurred in four of seven patients treated nonoperatively and radial nerve palsy occurred in another two. To the contrary, Groh et al. reported union in all five postoperative fractures treated nonoperatively.95 Nonunion after nonoperative treatment is typically managed with a combination of bone grafting, ORIF, and revision to a long-stemmed arthroplasty.147,297 
There are no large series demonstrating outcomes of operative management of periprosthetic humeral shaft fractures. Multiple small case series show relatively consistent results: high union rates with little effect on functional outcome in the absence of complications. Wutzler et al.299 reported on six patients with periprosthetic humeral shaft fractures all with well-fixed stems and all treated with plate fixation. Screws were used distally and either cables or screws or a combination of both were used for proximal fixation. Five of the six fractures healed without complication. One developed a nonunion requiring multiple surgeries and eventual revision to a long-stemmed prosthesis, bone grafting, and bone morphogenic protein to achieve union. This patient also had a persistent radial nerve palsy related to the initial periprosthetic fracture and was the only patient with a poor functional result in this series. Martinez et al.,176 based on union of six of six patients, advocated augmentation of a typical plate construct, screws distally and cables proximally, with strut allograft to improve stability. Just as in the femur, plate fixation for humeral periprosthetic fractures in the presence of a stable prosthesis with or without the addition of strut allografts is associated with good results. Therefore, the benefit of the adjuvant use of struts remains unclear. 
In the setting of a nonunion, the complexity of treatment increases. Kumar et al.147 treated five periprosthetic humeral fractures or nonunions after nonoperative treatment with revision arthroplasty (three with adjuvant allograft). One of the patients with nonunion had persistent nonunion after revision arthroplasty and ultimately required a free fibular transfer. 

Outcomes of Periprosthetic Scapula Fractures About Shoulder Arthroplasty

Outcomes after periprosthetic glenoid fractures about traditional TSA have been scarcely reported. 
Acromial fracture after reverse shoulder arthroplasty can have varying effects on outcome. Residual pain, even in the presence of a nonunion may be minimal, but function can be reduced.103 Union of acromial fractures with nonoperative treatment has been variable. Hamid et al.103 reported six nonunions out of eight fractures and Wahlquist et al.287 reported one of three fractures treated nonoperatively eventually requiring surgery to promote union. Fractures at the base of the acromion have been associated with poorer outcomes than more lateral fractures.109,159,287 In general, patients sustaining an acromial fracture can be expected to have minimal pain but poorer functional outcomes than those without fracture.159,288 

Potential Pitfalls and Preventative Measures for Treatment of Periprosthetic Fractures About Shoulder Arthroplasty

Operative intervention should not be considered mandatory for all periprosthetic humeral shaft fractures. Strong consideration for nonoperative management should be given to nondisplaced and minimally displaced fractures. Patients with more widely displaced fractures and those with fractures occurring shortly after shoulder arthroplasty, who require aggressive shoulder motion to achieve a good functional outcome, are less ideal candidates for nonoperative management. Given the typical necessity for cable fixation and the immediate proximity of the radial nerve to the posterior humerus in the zone of injury, there is substantial potential for injury to the radial nerve. Passing cables from an anterior approach, without the benefit of direct visualization of instrumentation relative to the radial nerve, is risky. Clear and careful delineation of the proximal and distal margins of the radial neurovascular bundle, as it crosses the posterior humerus, followed by dissection of the plane between the bundle and the posterior cortex is a good first step to avoid potential injury to the nerve. This bundle is often very wide and is less distinct than most other neurovascular bundles. Careful dissection of the plane between the bundle and the posterior cortex allows for visualization of fracture margins in this zone and for safe passage of plates beneath the bundle. A longer plate that allows easy access proximal to the bundle is preferred to aggressive retraction of the nerve to allow access to a shorter plate. The radial nerve is also very sensitive to traction injury. Retraction should avoid leverage (such as a Hohmann retractor placed between the bone and nerve) in favor of gentle controlled direct retraction such as with an army–navy retractor. 

Author’s Preferred Treatment of Periprosthetic Fractures about Shoulder Arthroplasty

 
 

Management of periprosthetic humeral fractures about shoulder arthroplasty stems is relatively straightforward and is based on the stability of the stem and the displacement of the fracture (Fig. 23-43). Most of these fractures occur about stable stems so revision arthroplasty is rarely required. Nondisplaced or minimally displaced fractures are managed nonoperatively with a fracture brace, similar to a native humeral shaft fracture, one that is not associated with a prosthesis. The indications for operative treatment are also similar to native humeral shaft fractures although the threshold for recommending operative treatment is somewhat lower. As opposed to native fractures that can be treated with either IMN or ORIF, operative treatment of periprosthetic fractures is limited to ORIF. A posterior approach is preferred to allow direct visualization and protection of the radial neurovascular bundle. A posterior large fragment plate is secured proximally with cables and distally with screws. Locked screws are utilized when osteoporotic bone is encountered.

Figure 23-43
Algorithm depicting the author’s preferred method of treatment for periprosthetic fractures about a total shoulder arthroplasty.
Rockwood-ch023-image043.png
View Original | Slide (.ppt)
X

Periprosthetic Fractures Elbow Arthroplasty

Incidence, Risk Factors, and Prevention of Periprosthetic Fractures About Elbow Arthroplasty

There are few large scale evaluations of periprosthetic fractures about total elbow prostheses. One notable exception is the Mayo Clinic experience with 1,072 linked Coonrad–Morrey procedures performed between 1983 and 2003. Periprosthetic fractures occurred with 9% of primary and 23% of revision procedures. These were equally distributed between fractures of the humerus and those of the ulna. All ulna fractures, in a different series of 30 consecutive fractures about a total elbow arthroplasty (TEA) treated surgically, were associated with loose components at a mean of 8 years after the index arthroplasty.78 Ulnar bone loss was considered moderate in 14 and severe in 6 of these cases. 
Risk factors specific to fracture about TEA have not been clearly elucidated because of the relative paucity of published data related to this topic. However, it is probably safe to consider that systemic or local conditions that reduce or weaken the bone stock in proximity to TEAs would predispose to periprosthetic fracture. 

Classification of Periprosthetic Fractures About Total Elbow Arthroplasty

O’Driscoll and Morrey203 classified humeral and ulnar periprosthetic fractures about total elbow components according to fracture location, component fixation, and bone quality, (Fig. 23-44). Type I fractures are metaphyseal, type II are of the shaft and in the zone of the stem, and type III are beyond the stem. As popularized by the Vancouver classification of periprosthetic femur fractures, periprosthetic elbow fractures are further subdivided by the status of the stem fixation. Subtype A fractures are well fixed and subtype Bs are associated with a loose implant. 
Figure 23-44
The Mayo classification of periprosthetic fractures about a total elbow arthroplasty.
 
Type I fractures are metaphyseal, Type II involve bone occupied by the implant, and Type III fractures extend beyond the stem. The subdivisions of these fractures are presented in the text.
Type I fractures are metaphyseal, Type II involve bone occupied by the implant, and Type III fractures extend beyond the stem. The subdivisions of these fractures are presented in the text.
View Original | Slide (.ppt)
Figure 23-44
The Mayo classification of periprosthetic fractures about a total elbow arthroplasty.
Type I fractures are metaphyseal, Type II involve bone occupied by the implant, and Type III fractures extend beyond the stem. The subdivisions of these fractures are presented in the text.
Type I fractures are metaphyseal, Type II involve bone occupied by the implant, and Type III fractures extend beyond the stem. The subdivisions of these fractures are presented in the text.
View Original | Slide (.ppt)
X

Management of Periprosthetic Fractures About Elbow Arthroplasty

Treatment of periprosthetic fractures about TEAs depends upon the location and displacement of the fracture, the time of occurrence (intra- or postoperative), the status of the implant (well fixed or loose), and the type of prosthesis (constrained or unconstrained). Type A fractures, those associated with a well-fixed component, are typically treated by either nonoperative means if nondisplaced or minimally displaced; otherwise, they are treated with ORIF. Type B fractures, those with a loose prosthesis, merit revision arthroplasty. 

Management of Periprosthetic Metaphyseal Fractures of the Humerus

Type I periprosthetic fractures of the humerus represent condylar fractures and may occur intraoperatively or postoperatively. Intraoperative fractures are associated with implant preparation in the metaphyseal region. Avulsion fracture of either the medial or lateral condyle can occur with stressing the collateral ligaments especially if bone resection was generous. This weakened area may be subject to spontaneous postoperative fracture or occur with minor trauma. Treatment of Type IA fractures, condylar fractures associated with well-fixed components, depends upon the prosthesis being used. A linked prosthesis such as the Coonrad–Morrey device does not rely upon the collateral ligaments for stability; therefore, these fractures with this implant type have little implications regarding prognosis. Therefore, nonoperative management is the mainstay so long as displacement is not so great as to compromise eventual union as nonunion may cause pain. In the setting of prostheses that rely upon the collateral ligaments for elbow stability, surgical fixation of these fractures is indicated. Peer-reviewed data to guide decision making for these fractures is lacking. 

Management of Periprosthetic Metaphyseal Fractures of the Ulna

Type I periprosthetic ulna fractures are either of the olecranon or coronoid. Coronoid fractures are very uncommon and usually occur intraoperatively. If the fragment is large, extends toward the diaphysis, or compromises ulnar stem fixation, then cable or wire fixation is performed. Type I fractures involving the olecranon are more likely to affect function as these fractures may disrupt the extensor mechanism. Thinning of the olecranon either because of systemic disease such as from RA or from intraoperative bone resection predisposes to fracture, and in these instances extreme care must be taken to avoid critical stress on the olecranon, particularly during intraoperative ulnar component trialing and forearm manipulation. Postoperative fracture can, of course, be related to direct trauma but may also occur spontaneously because of the force generated by triceps muscle contraction when there is compromised bone. Treatment is generally with ORIF utilizing a tension band technique for intraoperative fractures. Postoperative fractures are typically treated nonoperatively unless displacement is greater than approximately 2 cm. Nonunion has been reported in up to 50% of these fractures, but fibrous union and lack of displacement of more than 1 cm has been attributed to the generally good results despite lack of healing.175 

Management of Periprosthetic Diaphyseal Fractures of the Humerus and Ulna

Type IIA fractures of the humerus and of the ulna, diaphyseal fractures about well-fixed components, are very uncommon. They can theoretically occur at the time of implantation, especially if a long humeral component is inserted into an excessively bowed humerus. Fractures around the stem of the implant are more likely to occur postoperatively and be associated with osteolysis (Type IIB) or with relatively high-energy trauma. Treatment of these fractures should provide fracture stabilization, restoration of bone stock, and a stable prosthesis. The treatment principles follow that for the much more common and extensively studied Vancouver type B femoral fractures (Table 23-28). In the absence of a loose prosthesis, ORIF of a humeral shaft fracture with a strut allograft or plate can provide the required stability. ORIF with a plate and cable construct applied through a posterior approach is the most utilized means. Critical aspects of this procedure are identification and protection of the ulnar nerve distally and the radial nerve proximally. Formal exposure of the median nerve is generally not necessary as long as great care is taken to pass cables around the anterior aspect of the distal humerus adjacent to the anterior surface of the bone. Proximal fixation is with standard screws or, if the bone is osteoporotic, locked screws. A plate long enough to extend proximal to the radial neurovascular bundle allows ease of proximal screw fixation. The plate is gently slid beneath the bundle and fixed to the proximal fragment above and below the bundle. Historically, large fragment broad plates have been advocated for plating humeral fractures. However, with utilization of modern biologic fracture reduction techniques, the strength and associated bulk of these implants is somewhat excessive and narrow large fragment plates are now commonly utilized. Occasionally, fractures about the stem of the humeral component are nondisplaced or minimally displaced or the patient is otherwise not a candidate for surgery. In these cases, nonoperative treatment of the periprosthetic shaft fracture follows standard means with a fracture brace. 
 
Table 23-28
ORIF for Periprosthetic Fractures About Elbow Arthroplasty
Preoperative Planning Checklist
  •  
    OR table: Any table that allows fluoroscopy of the positioned arm
  •  
    Position/positioning aids:
    •  
      Humerus—lateral or prone with upper arm horizontal for posterior approach; supine for anterior approach
    •  
      Ulna—supine with arm over chest or lateral with forearm vertical
  •  
    Fluoroscopy location: Ipsilateral to fracture
  •  
    Equipment: Small and large fragment sets, cerclage cable system
  •  
    Tourniquet (sterile/nonsterile):
    •  
      Humerus—sterile
    •  
      Ulna—nonsterile
X
When the prosthesis is loose, implant revision with a long stem that bypasses the fracture provides intramedullary stability. Unlike the femur where canal-filling fully porous-coated stems are mainstream, long humeral stems do not reliably provide such stabilization. Therefore, plate or strut fixation is used. When bone deficiencies are present, strut allografts are indicated with or without an adjunctive plate. 
Successful use of a novel IMN technique for the management of such a nonunited fracture with massive bone loss has been reported.131 The fixation implant consisted of a custom IM nail and supplemental autologous bone graft. A commercially available cannulated nail was further hollowed at its distal end to form a sleeve that would nest over the stem of the humeral component. 
For fracture of the ulna shaft, plates are preferred if there is a stable implant with no associated bone loss. However, if there is significantly diminished bone stock, a strut allograft with or without a supplemental plate is typically utilized. Revision arthroplasty is indicated when there is a loose prosthesis on either side of the joint, osteolysis, or both. 
Fractures of the humerus and ulna distant to the stem tip are relatively uncommon and are usually associated with trauma and a loose stem. By definition, these fractures of the humerus are relatively proximal and may be difficult to control with splints or braces. Control of such fractures of the ulna is generally easier by closed means. Operative treatment is indicated for displaced fractures and those associated with a loose prosthesis (Fig. 23-45). The goals are to obtain stable fixation, adequate bone stock, and a stable prosthesis. When revision is indicated, a long stem is inserted across the fracture if practical. Regardless of stem position, ORIF with plates and struts are relied upon to provide fracture stability. 
Figure 23-45
A periprosthetic humerus fracture about the humeral component of a TEA (A) treated with ORIF (B).
Rockwood-ch023-image045.png
View Original | Slide (.ppt)
X

Outcomes for Periprosthetic Fractures About Total Elbow Arthroplasty

Foruria et al. 78 reported on a series of 30 periprosthetic ulna fractures, all were about loose components. Management included a variety of methods all including ulnar component revision. Strut allograft was utilized in 20 and impaction grafting techniques in eight. Three were revised with only impaction grafting and five were reconstructed with an allograft ulnar prosthetic composite. Twenty-one of these patients were ultimately available for follow-up at a mean of 4.9 years. Eighteen were with mild or no pain. The mean ROM of the elbow was 112 degrees and the mean Mayo Elbow Performance Score was 82. Fracture healing was achieved in all 21 of the followed patients. Complications included three deep infections, one case of ulnar component loosening, and one case of transient nerve palsy. 
Results of strut fixation of 11 humeral and 22 ulnar fractures revealed approximately 99% success at 3 to 5 years of both anatomic sites.127,244 

Author’s Preferred Treatment of Periprosthetic Fractures about Elbow Arthroplasty

 
 

Decision making for treatment of periprosthetic fractures about an elbow arthroplasty is relatively straightforward (Fig. 23-46). Diaphyseal fractures, or either the humerus or ulna, associated with a stable prosthesis are managed with ORIF. The preferred approach to the humeral shaft is posterior so that the radial and ulnar nerves can be directly visualized and protected. Passing cables from an anterior approach puts the radial nerve at substantial risk for injury given its immediate proximity to the posterior humeral cortex. Passing cables from posterior does not put the median nerve at such high risk as the median nerve is not in such close approximation to the anterior bone. Even when the prosthesis stem crosses the fracture, adjunctive ORIF is recommended. This is because long-stemmed humeral components are not canal filling and therefore provide little stability to the fracture. Long-stemmed ulna components provide marginal stability because they are typically either very thin or barely cross the fracture. Bone loss is managed with strut allografting. When diaphyseal fractures of either the humerus or ulna are associated with a loose component, revision arthroplasty is indicated.

 
Figure 23-46
Algorithm depicting the author’s preferred method of treatment for periprosthetic fractures about a total elbow arthroplasty.
Rockwood-ch023-image046.png
View Original | Slide (.ppt)
X
 

A special circumstance relates to periprosthetic metaphyseal fractures of the distal humerus. Management of these fractures considers the prosthesis type. Constrained or semiconstrained prostheses do not rely on ligamentous stability, so the epicondyles are not critical to prosthesis function. Therefore, metaphyseal fractures involving the epicondyles can often be treated nonoperatively, even if displaced. If displacement is so great that there is concern for nonunion, then ORIF is indicated. When these fractures occur around an unconstrained prosthesis, reduction and fixation is generally performed to restore ligamentous stability.

Special Circumstances, Expected Adverse Outcomes, and Unexpected Complications for Periprosthetic Fractures

The complications encountered during treatment of periprosthetic fractures is a compilation of the typical complication scene after acute fracture through native bone and the complications associated with joint arthroplasty. These can occur in isolation or in combination. Clearly, treatment must consider both the implications relative to the fracture and the implications with regard to arthroplasty stability and function. It is sometimes useful to prioritize the goals of treatment and decide if the outcome for the fracture is paramount or if preservation of the arthroplasty function is the primary goal. These are sometimes conflicting goals. 

Interprosthetic Fractures

Fractures between arthroplasties at opposite ends of a long bone have been termed interprosthetic fractures. As the number of patients with various joint arthroplasties increases, the likelihood of having a fracture that is between two existing arthroplasties similarly increases. Interprosthetic femur fractures between THA and TKA6,118,171,187,218,259 appear to be most common, but interprosthetic fractures of the humerus between TSA and TEA34,179 and of the tibia between TKA and TAA may also occur. As with any other femoral fractures, these interprosthetic fractures are typically treated operatively. In the upper extremity, nonoperative90,122 and operative34,179 management of interprosthetic humeral fractures has been described. 
Operative treatment of any interprosthetic fracture presents additional technical challenges relative to management of standard periprosthetic fractures. Extramedullary fixation, namely plate constructs, must account for interference by the associated arthroplasty in both the proximal and distal fracture fragments. Intramedullary devices, including nails and stemmed arthroplasty components that span the fracture, must be sized carefully so as to avoid interference from a stemmed component at the opposite end of the bone. For example, in the setting of an interprosthetic femoral shaft fracture between a stemmed THA component and a stemmed TKA component, a revision long stem THA femoral component must not be too long as to contact the stem of the TKA. When the final construct for management of an interprosthetic fracture leaves two stemmed components or a plate and an arthroplasty component in close proximity, the stress riser effect of each implant is potentially magnified. It is not surprising that in this patient population, who, by definition, have proven to be at risk for interprosthetic fracture, secondary interprosthetic fractures have been reported35,65 Plate fixation long enough to avoid a stress riser effect or the addition of a plate or strut graft to span a zone between two stemmed implants may be prudent to avoid future fracture. 

Nonunion

Nonunion is perhaps the most common complication associated with periprosthetic fractures. Nonunion rates for periprosthetic fracture fixation are generally higher than the rate for treatment of the same fracture in the absence of a prosthesis. It has been postulated that damage to the endosteal blood supply related to the intramedullary implant could alter the healing response to fracture, but this remains theory. A more influential cause of higher nonunion rates is the potentially compromised fixation caused by the prosthesis inhibiting optimal fixation. Cable fixation, the mainstay for plate or strut fixation around the zone of prostheses, has inferior strength compared to bicortical screws. However, advances in surgical technique and implant technologies have led to recent improvement in union rates. These advancements include biologic reduction techniques and the use of locked plates where locking screws can augment cable fixation in the zone of the implant and also augment fixation when osteopenic bone is encountered. Treatment of a periprosthetic nonunion can be extremely challenging. Results of nonunion repair of periprosthetic fracture are marginal. A multimodal approach is required.124 Correction of any systemic process that could inhibit fracture healing is done prior to nonunion repair. This consists of smoking cessation, discontinuation of NSAIDs, strict control of diabetes, and discontinuation of any other dispensable medications that could alter bone metabolism. Operative strategies include utilization of long stem prostheses in conjunction with extramedullary strut and plate fixation. Generous use of osteogenic and osteoinductive grafts and graft substitutes is imperative. Autologous iliac crest bone graft remains the gold standard, but rhBMP is a growing part of the armamentarium for these difficult cases. It goes without saying that restoration of anatomic limb alignment is another critical step. 

Infection

Infection may predate a periprosthetic fracture or may occur as a complication related to the treatment of one. A study evaluating inflammatory markers at the time of periprosthetic fracture associated with THA found evidence of infection to be present in 11.6% of 204 patients.42 The white blood cell count was elevated in 16.2%, the ESR increased in 33.3%, and the C-reactive protein level increased in 50.5%. The positive predictive value of these markers for infection were found to be poor, therefore clinical history is primarily relied upon to generate an index of suspicion for infection and operative findings are used for determining if infection should be considered during management. 
Infection can complicate any surgical procedure but when infection occurs after periprosthetic fracture it can be particularly devastating. Not only is fracture healing compromised but also the survivorship of the associated arthroplasty. Two competing goals must be addressed simultaneously: fracture stability and eradication of infection. Relatively aggressive early surgical treatment with irrigation and debridement and parental organism-specific antibiotics followed by long-term oral suppression has a potential to spare the fracture fixation and arthroplasty implants. Failure to control infection can have serious results including resection arthroplasty or amputation at or above the involved joint. Therefore, removal of the fracture fixation device, or the arthroplasty component, or removal of both should be considered. Use of antibiotic cement spacers typically used in the setting of infected joint arthroplasty in the absence of fracture may not provide adequate fixation in the setting of an associated nonunited fracture. Accordingly, infection surrounding a nonunited fracture associated with a joint arthroplasty often requires creative treatment means. To provide stability in such cases, the use of an antibiotic-impregnated cement-coated plate168 and the use of an interlocking prosthesis141 during staged treatment of a Vancouver B periprosthetic femur fracture have been successfully reported. 
There is little data specifically regarding infection after treatment of periprosthetic fractures. The majority of available data relates to periprosthetic femur fractures about hip stems. The rate of infection after modern treatment of Vancouver type B fractures with either ORIF or revision arthroplasty has been reported to be 5.94% in 202 cases210 and as high as 10%.141 Eleven of 17 patients with infected nonunited Vancouver type B periprosthetic femur fractures treated with debridement, removal of the hip stem, and replacement with an interlocking prosthesis eventually had definitive revision hip arthroplasty and were without residual evidence of infection.141 Of the other six patients, two had elevated inflammatory markers and were managed with long-term oral antibiotics with retention of the interlocking prosthesis and four were without serologic evidence of infection but electively retained the interlocking prosthesis. All 17 patients were without clinical evidence of infection at the final follow-up. The success of this strategy was attributed to the lack of ingrowth potential with the utilized locking prosthesis. This affords the opportunity for relatively easy revision to a definitive ingrowth prosthesis and also provides a reasonable long-term solution for low-demand patients unfit or unwilling to undergo such revision. 
The use of structural allograft has been implicated to increase infection rates although it remains unclear if the use of allograft is an independent risk factor for infection.283 Other factors commonly associated with the use of structural allograft such as length of operation, wound complications, inadequate soft tissue coverage, presence of nonunion, and multiple prior operations may influence the risk of infection. Management of an established infection associated with structural allograft usually involves complete removal of the allograft. Because the allograft is a nonvascular organic tissue, it serves as an optimal environment for bacterial growth. The lack of perfusion makes antibiotics and host immune responses ineffective and therefore making removal necessary. 

Neurologic Injury

Neurologic injury associated with periprosthetic fracture is reported in a number of series especially with fixation of humeral fractures. One partial radial and two partial ulnar nerve palsies were reported in a series of 11 periprosthetic humeral shaft fractures.244 The proximity of the radial and ulnar nerves to the fracture, the fixation devices, and securing cerclage cables put these structures at particular risk for injury. The best strategy for dealing with neurologic injury is one based on prevention. Appropriate choice of surgical approach is the first step. We prefer to directly expose any and all nerves that are potentially compromised. Therefore, the posterior approach is preferred for access to the humeral shaft. This way, the radial nerve is precisely located and can be protected throughout the procedure. Gentle soft tissue handling is also important with avoidance of forceful or prolonged retraction of nerves. Passing cerclage cables can be a harrowing experience. There is no substitute for direct knowledge of nerve location and direct protection during passage of cables. 

Joint Stiffness

Treatment of any periarticular fracture can result in temporary or permanent stiffness of the involved joint because of contracture and scar of the surrounding soft tissues from the processes leading to and associated with the index joint arthroplasty as well as from the trauma of fracture and subsequent surgery. Immobilization of the joint as part of fracture care can compound the tendency for stiffness. These issues are also relevant to the treatment of periprosthetic fractures. Fortunately, by nature, most periprosthetic fractures are at some distance from the involved joint and by definition are not intra-articular. Nevertheless, every effort should be made to obtain stable enough fixation to minimize the requirement for joint immobilization and to allow as early as possible ROM exercises. Hoffmann et al.115 reported that most patient in their series treated for a supracondylar periprosthetic femur fracture had loss of ROM with 13.5% having loss of extension of greater than 5 degrees. A shortcoming of this and similar reports is that any loss of motion related to the fracture is difficult to differentiate from baseline loss of motion related to the joint arthroplasty. This is an inherent problem with the evaluation of ROM related to any periprosthetic fracture. By definition, the affected joint is not normal by virtue of having been subjected to surgical joint replacement. This is unlike fractures about native joints, where a careful history producing no prior issues with joint mobility makes baseline ROM equal to the contralateral joint a reasonable assumption. 

References

Aaron RK, Scott R. Supracondylar fracture of the femur after total knee arthroplasty. Clin Orthop Relat Res. 1987;(219):136–139.
Abhaykumar S, Elliott DS. Percutaneous plate fixation for periprosthetic femoral fractures–a preliminary report. Injury. 2000;31(8):627–630.
Alden KJ, Duncan WH, Trousdale RT, et al. Intraoperative fracture during primary total knee arthroplasty. Clin Orthop Relat Res. 2010;468(1):90–95.
Althausen PL, Lee MA, Finkemeier CG, et al. Operative stabilization of supracondylar femur fractures above total knee arthroplasty: A comparison of four treatment methods. J Arthroplasty. 2003;18(7):834–839.
Amstutz HC, Campbell PA, Le Duff MJ. Fracture of the neck of the femur after surface arthroplasty of the hip. J Bone Joint Surg Am. 2004;86-A(9):1874–1877.
Anakwe RE, Aitken SA, Khan LA. Osteoporotic periprosthetic fractures of the femur in elderly patients: Outcome after fixation with the LISS plate. Injury. 2008;39(10):1191–1197.
Anderson AW, Polga DJ, Ryssman DB, et al. Case report: The nest technique for management of a periprosthetic patellar fracture with severe bone loss. Knee. 2009;16(4):295–298.
Andrews P, Barrack RL, Harris WH. Stress fracture of the medial wall of the acetabulum adjacent to a cementless acetabular component. J Arthroplasty. 2002;17(1):117–120.
Anglin C, Masri BA, Tonetti J, et al. Hip resurfacing femoral neck fracture influenced by valgus placement. Clin Orthop Relat Res. 2007;465:71–79.
Athwal GS, Sperling JW, Rispoli DM, et al. Periprosthetic humeral fractures during shoulder arthroplasty. J Bone Joint Surg Am. 2009;91(3):594–603.
Ayers DC. Supracondylar fracture of the distal femur proximal to a total knee replacement. Instr Course Lect. 1997;46:197–203.
Back DL, Dalziel R, et al. Early results of primary Birmingham hip resurfacings. An independent prospective study of the first 230 hips. J Bone Joint Surg Br. 2005;87(3):324–329.
Beals RK, Tower SS. Periprosthetic fractures of the femur. An analysis of 93 fractures. Clin Orthop. 1996;(327):238–246.
Berger RA, Meneghini RM, Jacobs JJ, et al. Results of unicompartmental knee arthroplasty at a minimum of ten years of follow-up. J Bone Joint Surg Am. 2005;87(5):999–1006.
Beris AE, Lykissas MG, Sioros V, et al. Femoral periprosthetic fracture in osteoporotic bone after a total knee replacement: Treatment with Ilizarov external fixation. J Arthroplasty. 2010;25(7):1168–1112.
Berry DJ. Epidemiology: Hip and knee. Orthop Clin North Am. 1999;30(2):183–190.
Bethea JS III, DeAndrade JR, Fleming LL, et al. Proximal femoral fractures following total hip arthroplasty. Clin Orthop Relat Res. 1982;(170):95–106.
Bhattacharyya T, Chang D, Meigs JB, et al. Mortality after periprosthetic fracture of the femur. J Bone Joint Surg Am. 2007;89(12):2658–2662.
Bobak P, Polyzois I, Graham S, et al. Nailed cementoplasty: A salvage technique for rorabeck type II periprosthetic fractures in octogenarians. J Arthroplasty. 2010;25(6):939–944.
Bogoch E, Hastings D, Gross A, et al. Supracondylar fractures of the femur adjacent to resurfacing and MacIntosh arthroplasties of the knee in patients with rheumatoid arthritis. Clin Orthop Relat Res. 1988;(229):213–220.
Bonutti PM, Hawkins RJ. Fracture of the humeral shaft associated with total replacement arthroplasty of the shoulder. A case report. J Bone Joint Surg Am. 1992;74(4):617–618.
Borrelli J Jr, Kantor J, Ungacta F, et al. Intraneural sciatic nerve pressures relative to the position of the hip and knee: A human cadaveric study. J Orthop Trauma. 2000;14(4):255–258.
Boyd AD Jr, Thornhill TS, Barnes CL. Fractures adjacent to humeral prostheses. J Bone Joint Surg Am. 1992;74(10):1498–1504.
Brady OH, Garbuz DS, Masri BA, et al. The treatment of periprosthetic fractures of the femur using cortical onlay allograft struts. Orthop Clin North Am. 1999;30(2):249–257.
Brady OH, Garbuz DS, Masri BA, et al. The reliability and validity of the Vancouver classification of femoral fractures after hip replacement. J.Arthroplasty. 2000;15(1):59–62.
Brick GW, Scott RD. The patellofemoral component of total knee arthroplasty. Clin Orthop Relat Res. 1988;(231):163–178.
Brumby SA, Carrington R, Zayontz S, et al. Tibial plateau stress fracture: A complication of unicompartmental knee arthroplasty using 4 guide pinholes. J Arthroplasty. 2003;18(6):809–812.
Bryant GK, Morshed S, Agel J, et al. Isolated locked compression plating for Vancouver Type B1 periprosthetic femoral fractures. Injury. 2009;40(11):1180–1186.
Buttaro MA, Farfalli G, Paredes NM, et al. Locking compression plate fixation of Vancouver type-B1 periprosthetic femoral fractures. J Bone Joint Surg Am. 2007;89(9):1964–1969.
Cain PR, Rubash HE, Wissinger HA, et al. Periprosthetic femoral fractures following total knee arthroplasty. Clin Orthop Relat Res. 1986;(208):205–214.
Cameron HU, Jung YB. Noncemented stem tibial component in total knee replacement: The 2- to 6-year results. Can J Surg. 1993;36(6):555–559.
Campbell JT, Moore RS, Iannotti JP, et al. Periprosthetic humeral fractures: Mechanisms of fracture and treatment options. J Shoulder Elbow Surg. 1998;7(4):406–413.
Carpentier K, Govaers K. Internal fixation of an intertrochanteric femoral fracture after Birmingham hip resurfacing arthroplasty. Acta Orthop Belg. 2012;78(2):275–278.
Carroll EA, Lorich DG, Helfet DL. Surgical management of a periprosthetic fracture between a total elbow and total shoulder prostheses: A case report. J Shoulder Elbow Surg. 2009;18(3):e9–e12.
Chakravarthy J, Bansal R, Cooper J. Locking plate osteosynthesis for Vancouver Type B1 and Type C periprosthetic fractures of femur: A report on 12 patients. Injury. 2007;38(6):725–733.
Chalidis BE, Tsiridis E, Tragas AA, et al. Management of periprosthetic patellar fractures. A systematic review of literature. Injury. 2007;38(6):714–724.
Chana R, Mansouri R, Jack C, et al. The suitability of an uncemented hydroxyapatite coated (HAC) hip hemiarthroplasty stem for intra-capsular femoral neck fractures in osteoporotic elderly patients: The Metaphyseal-Diaphyseal Index, a solution to preventing intra-operative periprosthetic fracture. J Orthop Surg Res. 2011;6:59.
Chandler HP, King D, Limbird R, et al. The use of cortical allograft struts for fixation of fractures associated with well-fixed total joint prostheses. Semin Arthroplasty. 1993;4(2):99–107.
Chandler HP, Tigges RG. The role of allografts in the treatment of periprosthetic femoral fractures. Instr Course Lect. 1998;47:257–264.
Chatoo M, Parfitt J, Pearse MF. Periprosthetic acetabular fracture associated with extensive osteolysis. J Arthroplasty. 1998;13(7):843–845.
Chettiar K, Jackson MP, Brewin J, et al. Supracondylar periprosthetic femoral fractures following total knee arthroplasty: Treatment with a retrograde intramedullary nail. Int Orthop. 2009;33(4):981–985.
Chevillotte CJ, Ali MH, Trousdale RT, et al. Inflammatory laboratory markers in periprosthetic hip fractures. J Arthroplasty. 2009;24(5):722–727.
Chun KA, Ohashi K, Bennett DL, et al. Patellar fractures after total knee replacement. AJR Am J Roentgenol. 2005;185(3):655–660.
Clarius M, Haas D, Aldinger PR, et al. Periprosthetic tibial fractures in unicompartmental knee arthroplasty as a function of extended sagittal saw cuts: An experimental study. Knee. 2010;17(1):57–60.
Clatworthy MG, Ballance J, Brick GW, et al. The use of structural allograft for uncontained defects in revision total knee arthroplasty. A minimum five-year review. J Bone Joint Surg Am. 2001;83-A(3):404–411.
Cook RE, Jenkins PJ, Walmsley PJ, et al. Risk factors for periprosthetic fractures of the hip: A survivorship analysis. Clin Orthop Relat Res. 2008;466(7):1652–1656.
Cooper HJ, Rodriguez JA. Early post-operative periprosthetic femur fracture in the presence of a non-cemented tapered wedge femoral stem. HSS J. 2010;6(2):150–154.
Corten K, Macdonald SJ, McCalden RW, et al. Results of cemented femoral revisions for periprosthetic femoral fractures in the elderly. J Arthroplasty. 2012;27(2):220–225.
Corten K, Vanrykel F, Bellemans J, et al. An algorithm for the surgical treatment of periprosthetic fractures of the femur around a well-fixed femoral component. J Bone Joint Surg Br. 2009;91(11):1424–1430.
Cossey AJ, Back DL, Shimmin A, et al. The nonoperative management of periprosthetic fractures associated with the Birmingham hip resurfacing procedure. J Arthroplasty. 2005;20(3):358–361.
Cracchiolo A. Stress fractures of the pelvis as a cause of hip pain following total hip and knee arthroplasty. Arthritis Rheum. 1981;24(5):740–742.
Crosby LA, Hamilton A, Twiss T. Scapula fractures after reverse total shoulder arthroplasty: Classification and treatment. Clin Orthop Relat Res. 2011;469(9):2544–2549.
Culp RW, Schmidt RG, Hanks G, et al. Supracondylar fracture of the femur following prosthetic knee arthroplasty. Clin Orthop Relat Res. 1987;(222):212–222.
Cumming D, Fordyce MJ. Non-operative management of a peri-prosthetic subcapital fracture after metal-on-metal Birmingham hip resurfacing. J Bone Joint Surg Br. 2003;85(7):1055–1056.
Davila J, Malkani A, Paiso JM. Supracondylar distal femoral nonunions treated with a megaprosthesis in elderly patients: A report of two cases. J Orthop Trauma. 2001;15(8):574–578.
Davison BL. Varus collapse of comminuted distal femur fractures after open reduction and internal fixation with a lateral condylar buttress plate. Am J Orthop. 2003;32(1):27–30.
Dehghan N, Chehade M, McKee MD. Current perspectives in the treatment of periprosthetic upper extremity fractures. J Orthop Trauma. 25(suppl 2):S71–S76.
Della Valle CJ, Momberger NG, Paprosky WG. Periprosthetic fractures of the acetabulum associated with a total hip arthroplasty. Instr Course Lect. 2003;52:281–290.
Dennis MG, Simon JA, Kummer FJ, et al. Fixation of periprosthetic femoral shaft fractures occurring at the tip of the stem: A biomechanical study of 5 techniques. J Arthroplasty. 2000;15(4):523–528.
Dennis MG, Simon JA, Kummer FJ, et al. Fixation of periprosthetic femoral shaft fractures: A biomechanical comparison of two techniques. J Orthop Trauma. 2001;15(3):177–180.
Desai G, Ries MD. Early postoperative acetabular discontinuity after total hip arthroplasty. J Arthroplasty. 2011;26(8):1570, e17–e19.
Dhawan RK, Mangham DC, Graham NM. Periprosthetic femoral fracture due to biodegradable cement restrictor. J Arthroplasty. 2012;27(8):1581, e13–15.
Doets HC, Brand R, Nelissen RG. Total ankle arthroplasty in inflammatory joint disease with use of two mobile-bearing designs. J Bone Joint Surg Am. 2006;88(6):1272–1284.
Duncan CP, Masri BA. Fractures of the femur after hip replacement. Instr Course Lect. 1995;44:293–304.
Duwelius PJ, Schmidt AH, Kyle RF, et al. A prospective, modernized treatment protocol for periprosthetic femur fractures. Orthop Clin North Am. 2004;35(4):485–492.
Ebraheim NA, Gomez C, Ramineni SK, et al. Fixation of periprosthetic femoral shaft fractures adjacent to a well-fixed femoral stem with reversed distal femoral locking plate. J Trauma. 2009;66(4):1152–1157.
Egol KA, Kubiak EN, Fulkerson E, et al. Biomechanics of locked plates and screws. J Orthop Trauma. 2004;18(8):488–493.
Ehlinger M, Adam P, Moser T, et al. Type C periprosthetic fractures treated with locking plate fixation with a mean follow up of 2.5 years. Orthop Traumatol Surg Res. 2010;96(1):44–48.
Ehlinger M, Bonnomet F, Adam P. Periprosthetic femoral fractures: the minimally invasive fixation option. Orthop Traumatol Surg Res. 2010;96(3):304–309.
Ehlinger M, Brinkert D, Besse J, et al. Reversed anatomic distal femur locking plate for periprosthetic hip fracture fixation. Orthop Traumatol Surg Res. 2011;97(5):560–564.
Engh GA, Ammeen DJ. Periprosthetic fractures adjacent to total knee implants: Treatment and clinical results. Instr Course Lect. 1998;47:437–448.
Erhardt JB, Grob K, Roderer G, et al. Treatment of periprosthetic femur fractures with the non-contact bridging plate: A new angular stable implant. Arch Orthop Trauma Surg. 2008;128(4):409–416.
Farfalli GL, Buttaro MA, Piccaluga F. Femoral fractures in revision hip surgeries with impacted bone allograft. Clin Orthop Relat Res. 2007;462:130–136.
Felix NA, Stuart MJ, Hanssen AD. Periprosthetic fractures of the tibia associated with total knee arthroplasty. Clin Orthop Relat Res. 1997;(345):113–124.
Figgie HE III, Goldberg VM, Figgie MP, et al. The effect of alignment of the implant on fractures of the patella after condylar total knee arthroplasty. J Bone Joint Surg Am. 1989;71(7):1031–1039.
Figgie MP, Goldberg VM, Figgie HE III, et al. The results of treatment of supracondylar fracture above total knee arthroplasty. J Arthroplasty. 1990;5(3):267–276.
Fink B, Grossmann A, Singer J. Hip revision arthroplasty in periprosthetic fractures of vancouver type B2 and B3. J Orthop Trauma. 2012;26(4):206–211.
Foruria AM, Sanchez-Sotelo J, Oh LS, et al. The surgical treatment of periprosthetic elbow fractures around the ulnar stem following semiconstrained total elbow arthroplasty. J Bone Joint Surg Am. 2011;93(15):1399–1407.
Foster AP, Thompson NW, Wong J, et al. Periprosthetic femoral fractures–a comparison between cemented and uncemented hemiarthroplasties. Injury. 2005;36(3):424–429.
Frankle M, Siegal S, Pupello D, et al. The reverse shoulder prosthesis for glenohumeral arthritis associated with severe rotator cuff deficiency. A minimum two-year follow-up study of sixty patients. J Bone Joint Surg Am. 2005;87(8):1697–1705.
Franklin J, Malchau H. Risk factors for periprosthetic femoral fracture. Injury. 2007;38(6):655–660.
Fredin HO, Lindberg H, Carlsson AS. Femoral fracture following hip arthroplasty. Acta Orthop Scand. 1987;58(1):20–22.
Freedman EL, Hak DJ, Johnson EE, et al. Total knee replacement including a modular distal femoral component in elderly patients with acute fracture or nonunion. J Orthop Trauma. 1995;9(3):231–237.
Fulkerson E, Koval K, Preston CF, et al. Fixation of periprosthetic femoral shaft fractures associated with cemented femoral stems: A biomechanical comparison of locked plating and conventional cable plates. J Orthop Trauma. 2006;20(2):89–93.
Fulkerson E, Tejwani N, Stuchin S, et al. Management of periprosthetic femur fractures with a first generation locking plate. Injury. 2007;38(8):965–972.
Garcia-Cimbrelo E, Munuera L, Gil-Garay E. Femoral shaft fractures after cemented total hip arthroplasty. Int Orthop. 1992;16(1):97–100.
Garnavos C, Rafiq M, Henry AP. Treatment of femoral fracture above a knee prosthesis. 18 cases followed 0.5–14 years. Acta Orthop Scand. 1994;65(6):610–614.
Gaski GE, Scully SP. In brief: Classifications in brief: Vancouver classification of postoperative periprosthetic femur fractures. Clin Orthop Relat Res. 2011;469(5):1507–1510.
Gelalis ID, Politis AN, Arnaoutoglou CM, et al. Traumatic periprosthetic acetabular fracture treated by acute one-stage revision arthroplasty. A case report and review of the literature. Injury. 2010;41(4):421–424.
Gill DR, Cofield RH, Morrey BF. Ipsilateral total shoulder and elbow arthroplasties in patients who have rheumatoid arthritis. J Bone Joint Surg Am. 1999;81(8):1128–1137.
Gliatis J, Megas P, Panagiotopoulos E, et al. Midterm results of treatment with a retrograde nail for supracondylar periprosthetic fractures of the femur following total knee arthroplasty. J Orthop Trauma. 2005;19(3):164–170.
Goldberg VM, Figgie HE III, Inglis AE, et al. Patellar fracture type and prognosis in condylar total knee arthroplasty. Clin Orthop Relat Res. 1988;(236):115–122.
Grace J N, Sim FH. Fracture of the patella after total knee arthroplasty. Clin Orthop Relat Res. 1988;(230):168–175.
Gras F, Marintschev I, Klos K, et al. Navigated percutaneous screw fixation of a periprosthetic acetabular fracture. J Arthroplasty. 2010;25(7):1169–1164.
Groh GI, Heckman MM, Wirth MA, et al. Treatment of fractures adjacent to humeral prostheses. J Shoulder Elbow Surg. 2008;17(1):85–89.
Guidera KJ, Borrelli J Jr, Raney E, et al. Orthopaedic manifestations of Rett syndrome. J Pediatr Orthop. 1991;11(2):204–208.
Gujarathi N, Putti AB, Abboud RJ, et al. Risk of periprosthetic fracture after anterior femoral notching. Acta Orthop. 2009;80(5):553–556.
Haddad FS, Duncan CP, Berry DJ, et al. Periprosthetic femoral fractures around well-fixed implants:Use of cortical onlay allografts with or without a plate. J Bone Joint Surg Am. 2002;84-A(6):945–950.
Haddad FS, Marston RA, Muirhead-Allwood SK. The Dall-Miles cable and plate system for periprosthetic femoral fractures. Injury. 1997;28(7):445–447.
Haendlmayer KT, Fazly FM, Harris NJ. Periprosthetic fracture after total ankle replacement: Surgical technique. Foot Ankle Int. 2009;30(12):1233–1234.
Haidukewych GJ, Jacofsky DJ, Hanssen AD, et al. Intraoperative fractures of the acetabulum during primary total hip arthroplasty. J Bone Joint Surg Am. 2006;88(9):1952–1956.
Hailer NP, Garellick G, Karrholm J. Uncemented and cemented primary total hip arthroplasty in the Swedish Hip Arthroplasty Register. Acta Orthop. 2010;81(1):34–41.
Hamid N, Connor PM, Fleischli JF, et al. Acromial fracture after reverse shoulder arthroplasty. Am J Orthop (Belle Mead NJ). 2011;40(7):E125–E129.
Han HS, Oh KW, Kang SB. Retrograde intramedullary nailing for periprosthetic supracondylar fractures of the femur after total knee arthroplasty. Clin Orthop Surg. 2009;1(4):201–206.
Hardy DC, Delince PE, Yasik E, et al. Stress fracture of the hip. An unusual complication of total knee arthroplasty. Clin Orthop Relat Res. 1992;(281):140–144.
Harris B, Owen JR, Wayne JS, et al. Does femoral component loosening predispose to femoral fracture?: An in vitro comparison of cemented hips. Clin Orthop Relat Res. 2010;468(2):497–503.
Harvie P, Gundle R, Willett K. Traumatic periprosthetic acetabular fracture: Life threatening haemorrhage and a novel method of acetabular reconstruction. Injury. 2004;35(8):819–822.
Haskell A, Mann RA. Perioperative complication rate of total ankle replacement is reduced by surgeon experience. Foot Ankle Int. 2004;25(5):283–289.
Hattrup SJ. The influence of postoperative acromial and scapular spine fractures on the results of reverse shoulder arthroplasty. Orthopedics. 2010;33(5).
Healy WL, Wasilewski SA, Takei R, et al. Patellofemoral complications following total knee arthroplasty. Correlation with implant design and patient risk factors. J Arthroplasty. 1995;10(2):197–201.
Heckler MW, Tennant GS, Williams DP, et al. Retrograde nailing of supracondylar periprosthetic femur fractures: A surgeon’s guide to femoral component sizing. Orthopedics. 2007;30(5):345–348.
Hendel D, Yasin M, Garti A, et al. Fracture of the greater trochanter during hip replacement: A retrospective analysis of 21/372 cases. Acta Orthop Scand. 2002;73(3):295–297.
Herrera DA, Kregor PJ, Cole PA, et al. Treatment of acute distal femur fractures above a total knee arthroplasty: Systematic review of 415 cases (1981-2006). Acta Orthop. 2008;79(1):22–27.
Hirsh DM, Bhalla S, Roffman M. Supracondylar fracture of the femur following total knee replacement. Report of four cases. J Bone Joint Surg Am. 1981;63(1):162–163.
Hoffmann MF, Jones CB, Sietsema DL, et al. Outcome of periprosthetic distal femoral fractures following knee arthroplasty. Injury. 2012;43(7):1084–1089.
Holden CE. The role of blood supply to soft tissue in the healing of diaphyseal fractures. An experimental study. J Bone Joint Surg Am. 1972;54(5):993–1000.
Hou Z, Bowen TR, Irgit K, et al. Locked plating of periprosthetic femur fractures above total knee arthroplasty. J Orthop Trauma. 2012;26(7):427–432.
Hou Z, Moore B, Bowen TR, et al. Treatment of interprosthetic fractures of the femur. J Trauma. 2011;71(6):1715–1719.
Hozack WJ, Goll SR, Lotke PA, et al. The treatment of patellar fractures after total knee arthroplasty. Clin Orthop Relat Res. 1988;(236):123–127.
Hsieh PH, Chang YH, Lee PC, et al. Periprosthetic fractures of the greater trochanter through osteolytic cysts with uncemented Microstructured Omnifit prosthesis: Retrospective analyses pf 23 fractures in 887 hips after 5-14 years. Acta Orthop. 2005;76(4):538–543.
Incavo SJ, Beard DM, Pupparo F, et al. One-stage revision of periprosthetic fractures around loose cemented total hip arthroplasty. Am J Orthop. 1998;27(1):35–41.
Inglis AE, Inglis AE Jr. Ipsilateral total shoulder arthroplasty and total elbow replacement arthroplasty: A caveat. J Arthroplasty. 2000;15(1):123–125.
Jacobs MA, Kennedy WR, Bhargava T, et al. Postresurfacing periprosthetic femoral neck fractures: Nonoperative treatment. Orthopedics. 2012;35(5):e732–e736.
Jani MM, Ricci WM, Borrelli J, et al. A protocol for treatment of unstable ankle fractures using transarticular fixation in patients with diabetes mellitus and loss of protective sensibility. Foot Ankle Int. 2003;24(11):838–844.
Johansson JE, McBroom R, Barrington TW, et al. Fracture of the ipsilateral femur in patients wih total hip replacement. J Bone Joint Surg Am. 1981;63(9):1435–1442.
Jonas SC, Walton MJ, Sarangi PP. Management of a periprosthetic fracture after humeral head resurfacing total shoulder replacement: A case report. J Shoulder Elbow Surg. 2011;20(5):e18–e21.
Kamineni S, Morrey BF. Proximal ulnar reconstruction with strut allograft in revision total elbow arthroplasty. J Bone Joint Surg Am. 2004;86-A(6):1223–1229.
Kampshoff J, Stoffel KK, Yates PJ, et al. The treatment of periprosthetic fractures with locking plates: Effect of drill and screw type on cement mantles: A biomechanical analysis. Arch Orthop Trauma Surg. 2010;130(5):627–632.
Katzer A, Ince A, Wodtke J, et al. Component exchange in treatment of periprosthetic femoral fractures. J Arthroplasty. 2006;21(4):572–579.
Kavanagh BF. Femoral fractures associated with total hip arthroplasty. Orthop Clin North Am. 1992;23(2):249–257.
Kawano Y, Okazaki M, Ikegami H, et al. The “docking” method for periprosthetic humeral fracture after total elbow arthroplasty: A case report. J Bone Joint Surg Am. 2010;92(10):1988–1991.
Keating EM, Haas G, Meding JB. Patella fracture after post total knee replacements. Clin Orthop Relat Res. 2003;(416):93–97.
Kellett CF, Boscainos PJ, Maury AC, et al. Proximal femoral allograft treatment of Vancouver type-B3 periprosthetic femoral fractures after total hip arthroplasty. Surgical technique. J Bone Joint Surg Am. 2007;89(suppl 2 Pt.1):68–79.
Kim DH, Clavert P, Warner JJ. Displaced periprosthetic humeral fracture treated with functional bracing: A report of two cases. J Shoulder Elbow Surg. 2005;14(2):221–223.
Kim YS, Callaghan JJ, Ahn PB, et al. Fracture of the acetabulum during insertion of an oversized hemispherical component. J Bone Joint Surg Am. 1995;77(1):111–117.
Kim KT, Lee S, Cho KH, et al. Fracture of the medial femoral condyle after unicompartmental knee arthroplasty. J Arthroplasty. 2009;24(7):1143–1144.
Klein GR, Parvizi J, Rapuri V, et al. Proximal femoral replacement for the treatment of periprosthetic fractures. J Bone Joint Surg Am. 2005;87(8):1777–1781.
Kolb W, Guhlmann H, Windisch C, et al. Fixation of periprosthetic femur fractures above total knee arthroplasty with the less invasive stabilization system: A midterm follow-up study. J Trauma. 2010;69(3):670–676.
Kolb K, Koller H, Lorenz I, et al. Operative treatment of distal femoral fractures above total knee arthroplasty with the indirect reduction technique: A long-term follow-up study. Injury. 2009;40(4):433–439.
Kolstad K. Revision THR after periprosthetic femoral fractures. An analysis of 23 cases. Acta Orthop Scand. 1994;65(5):505–508.
Konan S, Rayan F, Manketelow AR, et al. The use of interlocking prostheses for both temporary and definitive management of infected periprosthetic femoral fractures. J Arthroplasty. 2011;26(8):1332–1337.
Kraay MJ, Goldberg VM, Figgie MP, et al. Distal femoral replacement with allograft/prosthetic reconstruction for treatment of supracondylar fractures in patients with total knee arthroplasty. J Arthroplasty. 1992;7(1):7–16.
Kregor PJ, Stannard JA, Zlowodzki M, et al. Treatment of distal femur fractures using the less invasive stabilization system: Surgical experience and early clinical results in 103 fractures. J Orthop Trauma. 2004;18(8):509–520.
Kress KJ, Scuderi GR, Windsor RE, et al. Treatment of nonunions about the knee utilizing custom total knee arthroplasty with press-fit intramedullary stems. The Journal of Arthroplasty. 1995;8(1):49–55.
Kumar A, Chambers I, Maistrelli G, et al. Management of periprosthetic fracture above total knee arthroplasty using intramedullary fibular allograft and plate fixation. J Arthroplasty. 2008;23(4):554–558.
Kumar A, Chambers I, Wong P. Periprosthetic fracture of the proximal tibia after lateral unicompartmental knee arthroplasty. J Arthroplasty. 2008;23(4):615–618.
Kumar S, Sperling JW, Haidukewych GH, et al. Periprosthetic humeral fractures after shoulder arthroplasty. J Bone Joint Surg Am. 2004;86-A(4):680–689.
Kumm DA, Rack C, et al. Subtrochanteric stress fracture of the femur following total knee arthroplasty. J Arthroplasty. 1997;12(5):580–583.
Langenhan R, Trobisch P, Ricart P, et al. Aggressive surgical treatment of periprosthetic femur fractures can reduce mortality: Comparison of open reduction and internal fixation versus a modular prosthesis nail. J Orthop Trauma. 2012;26(2):80–85.
Large TM, Kellam JF, Bosse MJ, et al. Locked plating of supracondylar periprosthetic femur fractures. J Arthroplasty. 2008;23(6 suppl 1):115–120.
Laurer HL, Wutzler S, Possner S, et al. Outcome after operative treatment of Vancouver type B1 and C periprosthetic femoral fractures: Open reduction and internal fixation versus revision arthroplasty. Arch Orthop Trauma Surg. 2011;131(7):983–989.
Lee KB, Cho SG, Hur CI, et al. Perioperative complications of HINTEGRA total ankle replacement: Our initial 50 cases. Foot Ankle Int. 2008;29(10):978–984.
Lee GC, Nelson CL, Virmani S, et al. Management of periprosthetic femur fractures with severe bone loss using impaction bone grafting technique. J Arthroplasty. 2010;25(3):405–409.
Lenz M, Perren SM, Gueorguiev B, et al. Underneath the cerclage: An ex vivo study on the cerclage-bone interface mechanics. Arch Orthop Trauma Surg. 2012;132(10):1467–1472.
Lenz M, Windolf M, Muckley T, et al. The locking attachment plate for proximal fixation of periprosthetic femur fractures–a biomechanical comparison of two techniques. Int Orthop. 2012;36(9):1915–1921.
Lesh ML, Schneider DJ, Deol G, et al. The consequences of anterior femoral notching in total knee arthroplasty. A biomechanical study. J Bone Joint Surg Am. 2000;82-A(8):1096–1101.
Lesniewski PJ, Testa NN. Stress fracture of the hip as a complication of total knee replacement. Case report. J Bone Joint Surg Am. 1982;64(2):304–306.
Levine BR, Della Valle CJ, Lewis P, et al. Extended trochanteric osteotomy for the treatment of vancouver B2/B3 periprosthetic fractures of the femur. J Arthroplasty. 2008;23(4):527–533.
Levy JC, Anderson C, Samson A. Classification of postoperative acromial fractures following reverse shoulder arthroplasty. J Bone Joint Surg Am. 2013;95(15):e104.
Lewallen DG, Berry DJ. Periprosthetic fracture of the femur after total hip arthroplasty: Treatment and results to date. Instr Course Lect. 1998;47:243–249.
Lewis PL, Rorabeck CH. Periprosthetic Fractures. In: Engh GA, Rorabeck CH, eds. Revision Total Knee Arthroplasty. Baltimore, MD: Williams & Wilkins; 1997: 275–295.
Li CH, Chen TH, Su YP, et al. Periprosthetic femoral supracondylar fracture after total knee arthroplasty with navigation system. J Arthroplasty. 2008;23(2):304–307.
Lindahl H. Epidemiology of periprosthetic femur fracture around a total hip arthroplasty. Injury. 2007;38(6):651–654.
Lindahl H, Garellick G, Regner H, et al. Three hundred and twenty-one periprosthetic femoral fractures. J Bone Joint Surg Am. 2006;88(6):1215–1222.
Lindahl H, Malchau H, Herberts P, et al. Periprosthetic femoral fractures classification and demographics of 1049 periprosthetic femoral fractures from the Swedish National Hip Arthroplasty Register. J Arthroplasty. 2005;20(7):857–865.
Lindahl H, Oden A, Garellick G, et al. The excess mortality due to periprosthetic femur fracture. A study from the Swedish National Hip Arthroplasty Register. Bone. 2007;40(5):1294–1298.
Lindstrand A, Stenstrom A, Ryd L, et al. The introduction period of unicompartmental knee arthroplasty is critical: A clinical, clinical multicentered, and radiostereometric study of 251 Duracon unicompartmental knee arthroplasties. J Arthroplasty. 2000;15(5):608–616.
Liporace FA, Yoon RS, Frank MA, et al. Use of an “antibiotic plate” for infected periprosthetic fracture in total hip arthroplasty. J Orthop Trauma. 2012;26(3):e18–e23.
Long JP, Bartel DL. Surgical variables affect the mechanics of a hip resurfacing system. Clin Orthop Relat Res. 2006;453:115–122.
Lotke PA, Ecker ML. Influence of positioning of prosthesis in total knee replacement. J Bone Joint Surg Am. 1977;59(1):77–79.
Mamczak CN, Gardner MJ, Bolhofner B, et al. Interprosthetic femoral fractures. J Orthop Trauma. 2010;24(12):740–744.
Maniar RN, Umlas ME, Rodriguez JA, et al. Supracondylar femoral fracture above a PFC posterior cruciate-substituting total knee arthroplasty treated with supracondylar nailing. A unique technical problem. J Arthroplasty. 1996;11(5):637–639.
Marker DR, Seyler TM, Jinnah RH, et al. Femoral neck fractures after metal-on-metal total hip resurfacing: A prospective cohort study. J Arthroplasty. 2007;22(7 suppl 3):66–71.
Markmiller M, Konrad G, Sudkamp N. Femur-LISS and distal femoral nail for fixation of distal femoral fractures: Are there differences in outcome and complications? Clin Orthop Relat Res. 2004;(426):252–257.
Marra G, Morrey BF, Gallay SH, et al. Fracture and nonunion of the olecranon in total elbow arthroplasty. J Shoulder Elbow Surg. 2006;15(4):486–494.
Martinez AA, Calvo A, Cuenca J, et al. Internal fixation and strut allograft augmentation for periprosthetic humeral fractures. J Orthop Surg (Hong Kong). 2011;19(2):191–193.
Masri BA, Meek RM, Duncan CP. Periprosthetic fractures evaluation and treatment. Clin Orthop Relat Res. 2004;(420):80–95.
Maury AC, Pressman A, Cayen B, et al. Proximal femoral allograft treatment of Vancouver type-B3 periprosthetic femoral fractures after total hip arthroplasty. J Bone Joint Surg Am. 2006;88(5):953–958.
Mavrogenis AF, Angelini A, Guerra E, et al. Humeral fracture between a total elbow and total shoulder arthroplasty. Orthopedics. 2011;34(4).
McDonough EB, Crosby LA. Periprosthetic fractures of the humerus. Am J Orthop. 2005;34(12):586–591.
McGarvey WC, Clanton TO, Lunz D. Malleolar fracture after total ankle arthroplasty: A comparison of two designs. Clin Orthop Relat Res. 2004;(424):104–110.
McLean AL, Patton JT, Moran M. Femoral replacement for salvage of periprosthetic fracture around a total hip replacement. Injury. 2012;43(7):1166–1169.
Meek RM, Garbuz DS, Masri BA, et al. Intraoperative fracture of the femur in revision total hip arthroplasty with a diaphyseal fitting stem. J Bone Joint Surg Am. 2004;86-A(3):480–485.
Meek RM, Norwood T, Smith R, et al. The risk of peri-prosthetic fracture after primary and revision total hip and knee replacement. J Bone Joint Surg Br. 2011;93(1):96–101.
Meneghini RM, Cornwell P, Guthrie M, et al. A novel method for prevention of intraoperative fracture in cementless hip arthroplasty: Vibration analysis during femoral component insertion. Surg Technol Int. 2010;20:334–339.
Merkel KD, Johnson EW Jr. Supracondylar fracture of the femur after total knee arthroplasty. J Bone Joint Surg Am. 1986;68(1):29–43.
Michla Y, Spalding L, Holland JP, et al. The complex problem of the interprosthetic femoral fracture in the elderly patient. Acta Orthop Belg. 2010;76(5):636–643.
Mikhail WE, Wretenberg PF, Weidenhielm LR, et al. Complex cemented revision using polished stem and morselized allograft. Minimum 5-years’ follow-up. Arch Orthop Trauma Surg. 1999;119(5–6):288–291.
Miller AJ. Late fracture of the acetabulum after total hip replacement. J Bone Joint Surg Br. 1972;54(4):600–606.
Mont MA, Maar DC. Fractures of the ipsilateral femur after hip arthroplasty. A statistical analysis of outcome based on 487 patients. J Arthroplasty. 1994;9(5):511–519.
Mont MA, Seyler TM, Ulrich SD, et al. Effect of changing indications and techniques on total hip resurfacing. Clin Orthop Relat Res. 2007;465:63–70.
Moran MC, Brick GW, Sledge CB, et al. Supracondylar femoral fracture following total knee arthroplasty. Clin Orthop. 1996;(324):196–209.
Morrey BF, Kavanagh BF. Complications with revision of the femoral component of total hip arthroplasty. Comparison between cemented and uncemented techniques. J Arthroplasty. 1992;7:71–79.
Mukundan C, Rayan F, Kheir E, et al. Management of late periprosthetic femur fractures: A retrospective cohort of 72 patients. Int Orthop. 2010;34(4):485–489.
Mulay S, Hassan T, Birtwistle S, et al. Management of types B2 and B3 femoral periprosthetic fractures by a tapered, fluted, and distally fixed stem. J Arthroplasty. 2005;20(6):751–756.
Muller M, Kaab M, Tohtz S, et al. Periprosthetic femoral fractures: Outcome after treatment with LISS internal fixation or stem replacement in 36 patients. Acta Orthop Belg. 2009;75(6):776–783.
Myerson MS, Mroczek K. Perioperative complications of total ankle arthroplasty. Foot Ankle Int. 2003;24(1):17–21.
Naqvi GA, Baig SA, Awan N. Interobserver and intraobserver reliability and validity of the Vancouver classification system of periprosthetic femoral fractures after hip arthroplasty. J Arthroplasty. 2012;27(6):1047–1050.
Naraghi AM, White LM. Magnetic resonance imaging of joint replacements. Semin Musculoskelet Radiol. 2006;10(1):98–106.
Neumann D, Thaler C, Dorn U. Management of Vancouver B2 and B3 femoral periprosthetic fractures using a modular cementless stem without allografting. Int Orthop. 2012;36(5):1045–1050.
Ng VY, Arnott L, McShane M. Periprosthetic femoral condyle fracture after total knee arthroplasty and saline-coupled bipolar sealing technology. Orthopedics. 2011;34(1):53.
Nicolay S, De Beuckeleer L, Stoffelen D, et al. Atraumatic bilateral scapular spine fracture several months after bilateral reverse total shoulder arthroplasty. Skeletal Radiol. 2013.
O’Driscoll SW, Morrey BF. Periprosthetic fractures about the elbow. Orthop Clin North Am. 1999;30(2):319–325.
Olsen RV, Munk PL, Lee MJ, et al. Metal artifact reduction sequence: Early clinical applications. Radiographics. 2000;20(3):699–712.
Ortiguera CJ, Berry DJ. Patellar fracture after total knee arthroplasty. J Bone Joint Surg Am. 2002;84-A(4):532–540.
O’Shea K, Quinlan JF, Kutty S, et al. The use of uncemented extensively porous-coated femoral components in the management of Vancouver B2 and B3 periprosthetic femoral fractures. J Bone Joint Surg Br. 2005;87(12):1617–1621.
Palance MD, Albareda J, Seral F. Subcapital stress fracture of the femoral neck after total knee arthroplasty. Int Orthop. 1994;18(5):308–309.
Pandit H, Murray DW, Dodd CA, et al. Medial tibial plateau fracture and the Oxford unicompartmental knee. Orthopedics. 2007;30(5 suppl):28–31.
Parvizi J, Jain N, Schmidt AH. Periprosthetic knee fractures. J Orthop Trauma. 2008;22(9):663–671.
Pavlou G, Panteliadis P, Macdonald D, et al. A review of 202 periprosthetic fractures–stem revision and allograft improves outcome for type B fractures. Hip Int. 2011;21(1):21–29.
Perren SM, Linke B, Schwieger K, et al. Aspects of internal fixation of fractures in porotic bone. Principles, technologies and procedures using locked plate screws. Acta Chir Orthop Traumatol Cech. 2005;72(2):89–97.
Peskun CJ, Townley JB, Schemitsch EH, et al. Treatment of periprosthetic fractures around hip resurfacings with cephalomedullary nails. J Arthroplasty. 2012;27(3):494, e1–e3.
Peters CL, Hennessey R, Barden RM, et al. Revision total knee arthroplasty with a cemented posterior-stabilized or constrained condylar prosthesis: A minimum 3-year and average 5-year follow-up study. J Arthroplasty. 1997;12(8):896–903.
Petersen MM, Lauritzen JB, Pedersen JG, et al. Decreased bone density of the distal femur after uncemented knee arthroplasty. A 1-year follow-up of 29 knees. Acta Orthop Scand. 1996;67(4):339–344.
Petersen MM, Olsen C, Lauritzen JB, et al. Changes in bone mineral density of the distal femur following uncemented total knee arthroplasty. J Arthroplasty. 1995;10(1):7–11.
Peterson CA, Lewallen DG. Periprosthetic fracture of the acetabulum after total hip arthroplasty. J Bone Joint Surg Am. 1996;78(8):1206–1213.
Platzer P, Schuster R, Aldrian S, et al. Management and outcome of periprosthetic fractures after total knee arthroplasty. J Trauma. 2010;68(6):1464–1470.
Platzer P, Schuster R, Luxl M, et al. Management and outcome of interprosthetic femoral fractures. Injury. 2011;42(11):1219–1225.
Pot JH, van Heerwaarden RJ, Patt TW. An unusual way of intramedullar fixation after a periprosthetic supracondylar femur fracture. J Arthroplasty. 2012;27(3):494–498.
Pressmar J, Macholz F, Merkert W, et al. [Results and complications in the treatment of periprosthetic femur fractures with a locked plate system.] Unfallchirurg. 2010;113(3):195–202.
Pritchett JW. Fracture of the greater trochanter after hip replacement. Clin Orthop Relat Res. 2001;(390):221–226.
Radcliffe SN, Smith DN. The Mennen plate in periprosthetic hip fractures. Injury. 1996;27(1):27–30.
Rand JA, Coventry MB. Stress fractures after total knee arthroplasty. J Bone Joint Surg Am. 1980;62(2):226–233.
Rawes ML, Patsalis T, Gregg PJ. Subcapital stress fractures of the hip complicating total knee replacement. Injury. 1995;26(6):421–423.
Rayan F, Dodd M, Haddad FS. European validation of the Vancouver classification of periprosthetic proximal femoral fractures. J Bone Joint Surg Br. 2008;90(12):1576–1579.
Rayan F, Konan S, Haddad FS. Uncemented revision hip arthroplasty in B2 and B3 periprosthetic femoral fractures - A prospective analysis. Hip Int. 2010;20(1):38–42.
Ricci WM, Bolhofner BR, Loftus T, et al. Indirect reduction and plate fixation, without grafting, for periprosthetic femoral shaft fractures about a stable intramedullary implant. J Bone Joint Surg Am. 2005;87(10):2240–2245.
Ricci WM, Borrelli J Jr. Operative management of periprosthetic femur fractures in the elderly using biological fracture reduction and fixation techniques. Injury. 2007;38(suppl 3):S53–S58.
Ricci WM, Haidukewych GJ. Periprosthetic femoral fractures. Instr Course Lect. 2009;58:105–115.
Ricci WM, Loftus T, Cox C, et al Locked plates combined with minimally invasive insertion technique for the treatment of periprosthetic supracondylar femur fractures above a total knee arthroplasty. J Orthop Trauma. 2006;20(3):190–196.
Richards CJ, Giannitsios D, Huk OL, et al. Risk of periprosthetic femoral neck fracture after hip resurfacing arthroplasty: Valgus compared with anatomic alignment. A biomechanical and clinical analysis. J Bone Joint Surg Am. 2008;90(suppl 3):96–101.
Ritter MA, Campbell ED. Postoperative patellar complications with or without lateral release during total knee arthroplasty. Clin Orthop Relat Res. 1987;(219):163–168.
Ritter MA, Carr K, Keating EM, et al. Tibial shaft fracture following tibial tubercle osteotomy. J Arthroplasty. 1996;11(1):117–119.
Ritter MA, Faris PM, Keating EM. Anterior femoral notching and ipsilateral supracondylar femur fracture in total knee arthroplasty. J Arthroplasty. 1988;3(2):185–187.
Ritter MA, Thong AE, Keating EM, et al. The effect of femoral notching during total knee arthroplasty on the prevalence of postoperative femoral fractures and on clinical outcome. J Bone Joint Surg Am. 2005;87(11):2411–2414.
Robinson DE, Lee MB, Smith EJ, et al. Femoral impaction grafting in revision hip arthroplasty with irradiated bone. J.Arthroplasty. 2002;17(7):834–840.
Rorabeck CH, Taylor JW. Classification of periprosthetic fractures complicating total knee arthroplasty. Orthop Clin North Am. 1999;30(2):209–214.
Rorabeck CH, Taylor JW. Periprosthetic fractures of the femur complicating total knee arthroplasty. Orthop Clin North Am. 1999;30(2):265–277.
Rudol G, Jackson MP, James SE. Medial tibial plateau fracture complicating unicompartmental knee arthroplasty. J Arthroplasty. 2007;22(1):148–150.
Saidi K, Ben-Lulu O, Tsuji M, et al. Supracondylar periprosthetic fractures of the knee in the elderly patients: A comparison of treatment using allograft-implant composites, standard revision components, distal femoral replacement prosthesis. J Arthroplasty. 2014;29(1):110–114.
Sakai R, Kikuchi A, Morita T, et al. Hammering sound frequency analysis and prevention of intraoperative periprosthetic fractures during total hip arthroplasty. Hip Int. 2011;21(6):718–723.
Saltzman CL, Amendola A, Anderson R, et al. Surgeon training and complications in total ankle arthroplasty. Foot Ankle Int. 2003;24(6):514–518.
Sanchez-Sotelo J, McGrory BJ, Berry DJ. Acute periprosthetic fracture of the acetabulum associated with osteolytic pelvic lesions: A report of 3 cases. J Arthroplasty. 2000;15(1):126–130.
Sanchez-Sotelo J, O’Driscoll S, Morrey BF. Periprosthetic humeral fractures after total elbow arthroplasty: Treatment with implant revision and strut allograft augmentation. J Bone Joint Surg Am. 2002;84-A(9):1642–1650.
Sarvilinna R, Huhtala H, Pajamaki J. Young age and wedge stem design are risk factors for periprosthetic fracture after arthroplasty due to hip fracture. A case-control study. Acta Orthop. 2005;76(1):56–60.
Sarvilinna R, Huhtala HS, Sovelius RT, et al. Factors predisposing to periprosthetic fracture after hip arthroplasty: A case (n = 31)-control study. Acta Orthop Scand. 2004;75(1):16–20.
Schandelmaier P, Partenheimer A, Koenemann B, et al. Distal femoral fractures and LISS stabilization. Injury. 2001;32(suppl 3):SC55–SC63.
Schuberth JM, Patel S, Zarutsky E. Perioperative complications of the Agility total ankle replacement in 50 initial, consecutive cases. J Foot Ankle Surg. 2006;45(3):139–146.
Schutz M, Muller M, Krettek C, et al. Minimally invasive fracture stabilization of distal femoral fractures with the LISS: A prospective multicenter study. Results of a clinical study with special emphasis on difficult cases. Injury. 2001;32(suppl 3):SC48–SC54.
Schwartz JT Jr, Mayer JG, Engh CA. Femoral fracture during non-cemented total hip arthroplasty. J Bone Joint Surg Am. 1989;71(8):1135–1142.
Scott RD, Turoff N, Ewald FC. Stress fracture of the patella following duopatellar total knee arthroplasty with patellar resurfacing. Clin Orthop Relat Res. 1982;(170):147–151.
Sharkey PF, Hozack WJ, Callaghan JJ, et al. Acetabular fracture associated with cementless acetabular component insertion: A report of 13 cases. J Arthroplasty. 1999;14(4):426–431.
Sheth NP, Pedowitz DI, Lonner JH. Periprosthetic patellar fractures. J Bone Joint Surg Am. 2007;89(10):2285–2296.
Shimmin AJ, Back D. Femoral neck fractures following Birmingham hip resurfacing: A national review of 50 cases. J Bone Joint Surg Br. 2005;87(4):463–464.
Singh JA, Jensen MR, Harmsen SW, et al. Are gender, comorbidity, and obesity risk factors for postoperative periprosthetic fractures after primary total hip arthroplasty? J Arthroplasty. 2013;28(1):126–131.
Singh JA, Jensen MR, Lewallen DG. Patient factors predict periprosthetic fractures after revision total hip arthroplasty. J Arthroplasty. 2012;27(8):1507–1512.
Sloper PJ, Hing CB, Donell ST, et al. Intra-operative tibial plateau fracture during unicompartmental knee replacement: A case report. Knee. 2003;10(4):367–369.
Sochart DH, Hardinge K. Nonsurgical management of supracondylar fracture above total knee arthroplasty. Still the nineties option. J Arthroplasty. 1997;12(7):830–834.
Soenen M, Migaud H, Bonnomet F, et al. Interprosthetic femoral fractures: Analysis of 14 cases. Proposal for an additional grade in the Vancouver and SoFCOT classifications. Orthop Traumatol Surg Res. 2011;97(7):693–698.
Springer BD, Berry DJ, Cabanela ME, et al. Early postoperative transverse pelvic fracture: A new complication related to revision arthroplasty with an uncemented cup. J Bone Joint Surg Am. 2005;87(12):2626–2631.
Steinmann SP, Cheung EV. Treatment of periprosthetic humerus fractures associated with shoulder arthroplasty. J Am Acad Orthop Surg. 2008;16(4):199–207.
Stiehl JB. Extended osteotomy for periprosthetic femoral fractures in total hip arthroplasty. Am J Orthop. 2006;35(1):20–23.
Streit MR, Merle C, Clarius M, et al. Late peri-prosthetic femoral fracture as a major mode of failure in uncemented primary hip replacement. J Bone Joint Surg Br. 2011;93(2):178–183.
Streubel PN, Gardner MJ, Morshed S, et al. Are extreme distal periprosthetic supracondylar fractures of the femur too distal to fix using a lateral locked plate? J Bone Joint Surg Br. 2010;92(4):527–534.
Streubel PN, Ricci WM, Wong A, et al. Mortality after distal femur fractures in elderly patients. Clin Orthop Relat Res. 2011;469(4):1188–1196.
Stuart MJ, Hanssen AD. Total knee arthroplasty: Periprosthetic tibial fractures. Orthop Clin North Am. 1999;30(2):279–286.
Su ET, DeWal H, Di Cesare PE. Periprosthetic femoral fractures above total knee replacements. J Am Acad Orthop Surg. 2004;12(1):12–20.
Tadross TS, Nanu AM, Buchanan MJ, et al. Dall-Miles plating for periprosthetic B1 fractures of the femur. J. Arthroplasty. 2000;15(1):47–51.
Talbot M, Zdero R, Schemitsch EH. Cyclic loading of periprosthetic fracture fixation constructs. J Trauma. 2008;64(5):1308–1312.
Taljanovic MS, Hunter TB, Miller MD, et al. Gallery of medical devices: Part 1: Orthopedic devices for the extremities and pelvis. Radiographics. 2005;25(3):859–870.
Taylor MM, Meyers MH, Harvey JP Jr. Intraoperative femur fractures during total hip replacement. Clin Orthop Relat Res. 1978;(137):96–103.
Tharani R, Nakasone C, Vince KG. Periprosthetic fractures after total knee arthroplasty. J Arthroplasty. 2005;20(4 suppl 2):27–32.
Thomas SR, Wilson AJ, Chambler A, et al. Outcome of Copeland surface replacement shoulder arthroplasty. J Shoulder Elbow Surg. 2005;14(5):485–491.
Thompson NW, McAlinden MG, Breslin E, et al. Periprosthetic tibial fractures after cementless low contact stress total knee arthroplasty. J Arthroplasty. 2001;16(8):984–990.
Thomsen MN, Jakubowitz E, Seeger JB, et al. Fracture load for periprosthetic femoral fractures in cemented versus uncemented hip stems: An experimental in vitro study. Orthopedics. 2008;31(7):653.
Tower SS, Beals RK. Fractures of the femur after hip replacement: The Oregon experience. Orthop Clin North Am. 1999;30(2):235–247.
Tria AJ Jr, Harwood DA, Alicea JA, et al. Patellar fractures in posterior stabilized knee arthroplasties. Clin Orthop Relat Res. 1994;(299):131–138.
Tsiridis E, Amin MS, Charity J, et al. Impaction allografting revision for B3 periprosthetic femoral fractures using a Mennen plate to contain the graft: A technical report. Acta Orthop Belg. 2007;73(3):332–338.
Tsiridis E, Haddad FS, Gie GA. The management of periprosthetic femoral fractures around hip replacements. Injury. 2003;34(2):95–105.
Tsiridis E, Narvani AA, Haddad FS, et al. Impaction femoral allografting and cemented revision for periprosthetic femoral fractures. J Bone Joint Surg Br. 2004;86(8):1124–1132.
Tsiridis E, Spence G, Gamie Z, et al. Grafting for periprosthetic femoral fractures: Strut, impaction or femoral replacement. Injury. 2007;38(6):688–697.
Van Houwelingen AP, Duncan CP. The pseudo A(LT) periprosthetic fracture: It’s really a B2. Orthopedics. 2011;34(9):e479–e481.
Van Houwelingen AP, Schemitsch EH. Infection associated with cortical allograft strut fixation of a periprosthetic femoral shaft fracture: A case report and review of the literature. J Trauma. 2008;64(6):1630–1634.
Van Loon P, de Munnynck B, Bellemans J. Periprosthetic fracture of the tibial plateau after unicompartmental knee arthroplasty. Acta Orthop Belg. 2006;72(3):369–374.
Venu KM, Koka R, Garikipati, R, et al. Dall-Miles cable and plate fixation for the treatment of peri-prosthetic femoral fractures-analysis of results in 13 cases. Injury. 2001;32(5):395–400.
Virolainen P, Mokka J, Seppanen M, et al. Up to 10 years follow up of the use of 71 cortical allografts (strut-grafts) for the treatment of periprosthetic fractures. Scand J Surg. 2010;99(4):240–243.
Wahlquist TC, Hunt AF, Braman JP. Acromial base fractures after reverse total shoulder arthroplasty: Report of five cases. J Shoulder Elbow Surg. 2011;20(7):1178–1183.
Walch G, Mottier F, Wall B, et al. Acromial insufficiency in reverse shoulder arthroplasties. J Shoulder Elbow Surg. 2009;18(3):495–502.
Wang CJ, Wang JW, Weng LH, et al. The effect of alendronate on bone mineral density in the distal part of the femur and proximal part of the tibia after total knee arthroplasty. J Bone Joint Surg Am. 2003;85-A(11):2121–2126.
White LM, Kim JK, Mehta M, et al. Complications of total hip arthroplasty: MR imaging-initial experience. Radiology. 2000;215(1):254–262.
Whittaker RP, Sotos LN, Ralston EL. Fractures of the femur about femoral endoprostheses. J Trauma. 1974;14(8):675–694.
Wick M, Muller EJ, Kutscha-Lissberg F, et al. [Periprosthetic supracondylar femoral fractures: LISS or retrograde intramedullary nailing? Problems with the use of minimally invasive technique]. Unfallchirurg. 2004;107(3):181–188.
Wilson FC, Venters GC. Results of knee replacement with the Walldius prosthesis: An interim report. Clin Orthop Relat Res. 1976;(120):39–46.
Wong P, Gross AE. The use of structural allografts for treating periprosthetic fractures about the hip and knee. Orthop Clin North Am. 1999;30(2):259–264.
Wood PL, Deakin S. Total ankle replacement. The results in 200 ankles. J Bone Joint Surg Br. 2003;85(3):334–341.
Worland RL, Kim DY, Arredondo J. Periprosthetic humeral fractures: Management and classification. J Shoulder Elbow Surg. 1999;8(6):590–594.
Wright TW, Cofield RH. Humeral fractures after shoulder arthroplasty. J Bone Joint Surg Am. 1995;77(9):1340–1346.
Wu CC, Au MK, Wu SS, et al. Risk factors for postoperative femoral fracture in cementless hip arthroplasty. J Formos Med Assoc. 1999;98(3):190–194.
Wutzler S, Laurer HL, Huhnstock S, et al. Periprosthetic humeral fractures after shoulder arthroplasty: Operative management and functional outcome. Arch Orthop Trauma Surg. 2009;129(2):237–243.
Xue H, Tu Y, Cai M, et al. Locking compression plate and cerclage band for type B1 periprosthetic femoral fractures preliminary results at average 30-month follow-up. J Arthroplasty. 2011;26(3):467–471.
Yang JH, Kim HJ, Yoon JR, et al. Minimally invasive plate osteosynthesis (MIPO) for periprosthetic fracture after total ankle arthroplasty: A case report. Foot Ankle Int. 2011;32(2):200–204.
Young SW, Walker CG, Pitto RP. Functional outcome of femoral peri prosthetic fracture and revision hip arthroplasty: A matched-pair study from the New Zealand Registry. Acta Orthop. 2008;79(4):483–488.
Zaki SH, Sadiq S, Purbach B, et al. Periprosthetic femoral fractures treated with a modular distally cemented stem. J Orthop Surg (Hong Kong). 2007;15(2):163–166.
Zalzal P, Backstein D, Gross AE, et al. Notching of the anterior femoral cortex during total knee arthroplasty characteristics that increase local stresses. J Arthroplasty. 2006;21(5):737–743.
Zalzal P, Gandhi R, Petruccelli D, et al. Fractures at the tip of long-stem prostheses used for revision hip arthroplasty. J. Arthroplasty. 2003;18(6):741–745.
Zdero R, Walker R, Waddell JP, et al. Biomechanical evaluation of periprosthetic femoral fracture fixation. J Bone Joint Surg Am. 2008;90(5):1068–1077.
Zeh A, Radetzki F, Diers V, et al. Is there an increased stem migration or compromised osteointegration of the Mayo short-stemmed prosthesis following cerclage wiring of an intrasurgical periprosthetic fracture? Arch Orthop Trauma Surg. 2011;131(12):1717–1722.
Zenni EJ Jr, Pomeroy DL, Caudle RJ. Ogden plate and other fixations for fractures complicating femoral endoprostheses. Clin Orthop. 1988;(231): 83–90.
Zustin J, Krause M, Breer S, et al. Morphologic analysis of periprosthetic fractures after hip resurfacing arthroplasty. J Bone Joint Surg Am. 2010;92(2):404–410.
Zuurmond RG, Pilot P, Verburg AD. Retrograde bridging nailing of periprosthetic femoral fractures. Injury. 2007;38(8):958–964.
Zuurmond RG, Pilot P, Verburg AD, et al. Retrograde bridging nail in periprosthetic femoral fracture treatment which allows direct weight bearing. Proc Inst Mech Eng H. 2008;222(5):629–635.
Zuurmond RG, van Wijhe W, van Raay JJ, et al. High incidence of complications and poor clinical outcome in the operative treatment of periprosthetic femoral fractures: An analysis of 71 cases. Injury. 2010;41(6):629–633.