Chapter 20: Distal Humeral Physeal, Medial Condyle, Lateral Epicondylar, and Other Uncommon Elbow Fractures

Michael P. Glotzbecker, James R. Kasser

Chapter Outline

Introduction

There are rare injuries about the elbow that can be underappreciated or missed acutely that have serious long-term implications for patients. We have labeled these as TRASH (The Radiographic Appearance Seemed Harmless) lesions about the elbow. Most commonly these occur in the very young before secondary centers of ossification would make the acute diagnosis and treatment easier. Examples of TRASH lesion are: (1) Distal humeral physeal fractures before the capitellum ossifies; (2) medial condylar fractures before the trochlea ossifies; and (3) osteochondral fractures in the children less than age 10 years that leads to joint incongruity and instability. Often additional radiographic evaluation with ultrasound, arthrography, and/or MRI scans is necessary to make the diagnosis acutely and intervene appropriately for the best long-term outcome. This chapter will cover many of the rare, potentially problematic injuries about the elbow. 

Introduction to Fractures Involving the Entire Distal Humerus

From 1960 to 1978, many individual patients who suffered a distal humeral physeal separation were reported.38,66,69,73 Once the presence of this injury became recognized, larger series appeared. Subsequently, seven separate series reported a total of 45 fractures,2,16,17,34,46,53,62 and Abe et al.1 reported a series of 21 fractures. Originally thought to be a rare injury, it appears that fractures involving the entire distal humeral physis occur frequently in children as they now have become more commonly reported. The major problem is the initial recognition of this injury. 
Most fractures involving the entire distal humeral physis occur before the age of 6 or 7 and are most common under the age of 2. The younger the child is, the greater the volume of the distal humerus epiphysis. As the humerus matures, the physeal line progresses more distally, with a central V forming between the medial and lateral condylar physes (Fig. 20-1). Ashurst3 believed that this V-shaped configuration of the physeal line helps protect the more mature distal humerus from physeal fractures. 
Figure 20-1
 
A: Group A—AP view of a small infant who had a swollen left elbow after a difficult delivery. The displacement medially of the proximal radius and ulna (arrows) helps to make the diagnosis of a displaced total distal humeral physis. B: Normal elbow for comparison. C: Group B—AP view showing the posteromedial displacement of the distal fragment (arrows). The relationship between the ossification center of the lateral condyle and the proximal radius has been maintained. D: Group C—AP view with marked medial displacement of the distal fragment. E: Group C—lateral view of the same patient showing posterior displacement of the distal fragment. There is also a large metaphyseal fragment associated with the distal fragment (arrow).
A: Group A—AP view of a small infant who had a swollen left elbow after a difficult delivery. The displacement medially of the proximal radius and ulna (arrows) helps to make the diagnosis of a displaced total distal humeral physis. B: Normal elbow for comparison. C: Group B—AP view showing the posteromedial displacement of the distal fragment (arrows). The relationship between the ossification center of the lateral condyle and the proximal radius has been maintained. D: Group C—AP view with marked medial displacement of the distal fragment. E: Group C—lateral view of the same patient showing posterior displacement of the distal fragment. There is also a large metaphyseal fragment associated with the distal fragment (arrow).
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A: Group A—AP view of a small infant who had a swollen left elbow after a difficult delivery. The displacement medially of the proximal radius and ulna (arrows) helps to make the diagnosis of a displaced total distal humeral physis. B: Normal elbow for comparison. C: Group B—AP view showing the posteromedial displacement of the distal fragment (arrows). The relationship between the ossification center of the lateral condyle and the proximal radius has been maintained. D: Group C—AP view with marked medial displacement of the distal fragment. E: Group C—lateral view of the same patient showing posterior displacement of the distal fragment. There is also a large metaphyseal fragment associated with the distal fragment (arrow).
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Figure 20-1
A: Group A—AP view of a small infant who had a swollen left elbow after a difficult delivery. The displacement medially of the proximal radius and ulna (arrows) helps to make the diagnosis of a displaced total distal humeral physis. B: Normal elbow for comparison. C: Group B—AP view showing the posteromedial displacement of the distal fragment (arrows). The relationship between the ossification center of the lateral condyle and the proximal radius has been maintained. D: Group C—AP view with marked medial displacement of the distal fragment. E: Group C—lateral view of the same patient showing posterior displacement of the distal fragment. There is also a large metaphyseal fragment associated with the distal fragment (arrow).
A: Group A—AP view of a small infant who had a swollen left elbow after a difficult delivery. The displacement medially of the proximal radius and ulna (arrows) helps to make the diagnosis of a displaced total distal humeral physis. B: Normal elbow for comparison. C: Group B—AP view showing the posteromedial displacement of the distal fragment (arrows). The relationship between the ossification center of the lateral condyle and the proximal radius has been maintained. D: Group C—AP view with marked medial displacement of the distal fragment. E: Group C—lateral view of the same patient showing posterior displacement of the distal fragment. There is also a large metaphyseal fragment associated with the distal fragment (arrow).
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A: Group A—AP view of a small infant who had a swollen left elbow after a difficult delivery. The displacement medially of the proximal radius and ulna (arrows) helps to make the diagnosis of a displaced total distal humeral physis. B: Normal elbow for comparison. C: Group B—AP view showing the posteromedial displacement of the distal fragment (arrows). The relationship between the ossification center of the lateral condyle and the proximal radius has been maintained. D: Group C—AP view with marked medial displacement of the distal fragment. E: Group C—lateral view of the same patient showing posterior displacement of the distal fragment. There is also a large metaphyseal fragment associated with the distal fragment (arrow).
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Assessment of Fractures Involving the Entire Distal Humerus

Mechanisms of Injury for Fractures Involving the Entire Distal Humerus

The exact mechanism of this injury is unknown and probably varies with the age group involved. A few consistent factors are evident. First, many fractures of the entire distal humeral physis have occurred as birth injuries associated with difficult deliveries.2,4,6,19,69 Siffert69 noted that the clinical appearance of these injured elbows at the time of delivery was not especially impressive. There was only moderate swelling and some crepitus. 
Second, DeLee et al.17 noted a high incidence of confirmed or suspected child abuse in their very young patients. Other reports2,16,49,56,79 have confirmed the frequency of child abuse in infants and young children with these fractures, and up to 50% of these fractures in children under the age of 2 may be the result of abuse. 
Bright9 showed that a physis is more likely to fail with rotary shear forces than with pure bending or tension forces. Young infants have some residual flexion contractures of the elbow from intrauterine positioning; this prevents the hyperextension injury that results in supracondylar elbow fractures in older children. Rotary or shear forces on the elbow, which can be caused by child abuse or birth trauma in young infants, are probably more responsible for this injury in young children. In older children, a hyperextension force on an outstretched arm may cause the injury. Abe et al.1 reported 21 children, ranging in age from 1 to 11 years (average: 5 years), with fracture separations of the distal humeral epiphysis, all of which were sustained in falls. 

Associated Injuries with Fractures Involving the Entire Distal Humerus

Child abuse should always be considered in children with this injury, especially a type A fracture pattern (see classification below), unless it occurs at birth. A young infant is unlikely to incur this type of injury spontaneously from the usual falls that occur during the first year of life. Of the 16 fractures reported by DeLee et al.,17 six resulted from documented or highly suspected child abuse, all in children younger than 2 years of age. Therefore, other injuries commonly found in cases of child abuse should be considered. If child abuse is suspected, a bone scan and a skeletal survey are warranted, to look for metaphyseal corner fractures, rib fractures, or fractures at various stages of healing, and the possibility of head trauma should not be ignored. 

Signs and Symptoms of Fractures Involving the Entire Distal Humerus

In an infant less than 18 months of age, whose elbow is swollen secondary to trauma or suspected trauma, a fracture involving the entire distal humeral physis should be considered. In a young infant or newborn, swelling may be minimal with little crepitus. Poland64 described the crepitus as “muffled” crepitus because the fracture ends are covered with softer cartilage than the firm osseous tissue in other fractures about the elbow. Because of the large, wide fracture surfaces, there are fewer tendencies for tilting with distal fragment rotation, and the angular deformity is less severe than that with supracondylar fractures. In older children, the elbow is often so swollen that a clinical assessment of the bony landmarks is impossible, and only radiographic evaluation can provide confirmation of the diagnosis. 

Imaging and Other Diagnostic Studies for Fractures Involving the Entire Distal Humerus

Confirming radiographic evidence of a distal humeral physeal separation can be difficult, especially if the ossification center of the lateral condyle is not visible in an infant. The only relationship that can be determined is that of the primary ossification centers of the distal humerus to the proximal radius and ulna. The proximal radius and ulna maintain an anatomic relationship to each other but are displaced posteriorly and medially in relation to the distal humerus. This posteromedial relationship is diagnostic. Although theoretically, the distal fragment can be displaced in any direction, with rare exceptions,6 most fractures reported have been displaced posteromedially. Comparison views of the opposite uninjured elbow may be helpful to determine the presence of posteromedial displacement (Fig. 20-1A, B). 
Distinguishing the injury from an elbow dislocation may be challenging. It should be remembered that elbow dislocations are rare in the peak age group for fractures of the entire distal humeral physis. With elbow dislocations, the displacement of the proximal radius and ulna is almost always posterolateral, and the relationship between the proximal radius and lateral condylar epiphysis is disrupted. Unfortunately, this can be especially difficult to assess in young children when the capitellum is not ossified. In contrast, the anatomic relationship of the lateral condylar epiphysis with the radial head is maintained with a transphyseal separation, even though the distal humeral epiphysis is displaced posterior and medial in relation to the metaphysis of the humerus. Once the lateral condylar epiphysis becomes ossified, displacement of the entire distal epiphysis is much more obvious. 
Because they have a large metaphyseal fragment, type C fractures may be confused with either a low supracondylar fracture or a fracture of the lateral condylar physis. The key diagnostic point is the smooth outline of the distal metaphysis in fractures involving the total distal physis. With supracondylar fractures, the distal portion of the distal fragment has a more irregular border. 
Differentiation from a fracture of the lateral condylar physis in an infant can be made on radiograph. With a displaced fracture of the lateral condylar physis, the relationship between the lateral condylar epiphysis and the proximal radius can be disrupted but may remain normal (Fig. 20-2). If the lateral crista of the trochlea is involved, the proximal radius and ulna may be displaced posterolaterally. Oblique radiographs or other advanced imaging may be needed to distinguish these injuries. 
Figure 20-2
Displaced fracture of the lateral condyle in a 2-year old.
 
The relationship of the lateral condyle (closed arrow) to the proximal radius is lost. Both the proximal radius and ulna (open arrow) have shifted slightly laterally.
The relationship of the lateral condyle (closed arrow) to the proximal radius is lost. Both the proximal radius and ulna (open arrow) have shifted slightly laterally.
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Figure 20-2
Displaced fracture of the lateral condyle in a 2-year old.
The relationship of the lateral condyle (closed arrow) to the proximal radius is lost. Both the proximal radius and ulna (open arrow) have shifted slightly laterally.
The relationship of the lateral condyle (closed arrow) to the proximal radius is lost. Both the proximal radius and ulna (open arrow) have shifted slightly laterally.
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If differentiation of this injury from an intra-articular fracture is uncertain, arthrography or MRI may be helpful (Fig. 20-3).56 In neonates and infants in whom ossification has not begun, ultrasonography can be used to identify the displaced epiphysis of the humerus (Fig. 20-4).18 
Figure 20-3
 
MRI (A) demonstrating transphyseal separation of the distal humerus and arthrogram (B, C) demonstrating realignment after pin fixation.
MRI (A) demonstrating transphyseal separation of the distal humerus and arthrogram (B, C) demonstrating realignment after pin fixation.
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MRI (A) demonstrating transphyseal separation of the distal humerus and arthrogram (B, C) demonstrating realignment after pin fixation.
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Figure 20-3
MRI (A) demonstrating transphyseal separation of the distal humerus and arthrogram (B, C) demonstrating realignment after pin fixation.
MRI (A) demonstrating transphyseal separation of the distal humerus and arthrogram (B, C) demonstrating realignment after pin fixation.
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MRI (A) demonstrating transphyseal separation of the distal humerus and arthrogram (B, C) demonstrating realignment after pin fixation.
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Figure 20-4
Sagittal ultrasound demonstrating posterior displacement of the distal humeral epiphysis.
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If the diagnosis is delayed, new periosteal bone forms around the distal humerus, and the whole epiphysis may remain displaced posteriorly and medially (Fig. 20-5). 
Figure 20-5
The true nature of this injury as involving the entire distal humeral physis was not appreciated until periosteal new bone became visible 3 weeks after injury.
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Classification of Fractures Involving the Entire Distal Humerus

DeLee et al.17 classified fractures of the entire distal humeral physis into three groups based on the degree of ossification of the lateral condylar epiphysis (Fig. 20-1). Group A fractures occur in infants up to 12 months of age, before the secondary ossification center of the lateral condylar epiphysis appears (Fig. 20-1A). They are usually Salter–Harris type I physeal injuries. This injury may be missed because of the lack of an ossification center in the lateral condylar epiphysis. Group B fractures occur most often in children of 12 months to 3 years of age in whom there is definite ossification of the lateral condylar epiphysis (Fig. 20-1C). Although there may be a small flake of metaphyseal bone, this is also essentially a type I Salter–Harris physeal injury. Group C fractures occur in older children, from 3 to 7 years of age and result in a large metaphyseal fragment that is most commonly lateral but can be medial or posterior (Fig. 20-1D, E). 
These fractures are almost always extension-type injuries with the distal epiphyseal fragment displacing posterior to the metaphysis. A rare flexion type of injury can occur in which the epiphyseal fragment is displaced anteriorly.6 Stricker et al.72 reported a coronal plane transcondylar (Salter–Harris type IV) fracture in a 3-year-old child that was initially diagnosed as a fracture of the lateral humeral condyle. No growth disturbance was evident 3 years after open reduction and pin fixation. 

Pathoanatomy and Applied Anatomy Relating to Fractures Involving the Entire Distal Humerus

Distal humeral physeal injuries have similar anatomic considerations as supracondylar humerus fractures. However, because the patients who suffer this injury are often very young, diagnosis and treatment can be more challenging. 
Because fractures coursing along the distal humeral physis traverse the anatomic centers of the condyles, they are the pediatric counterparts of the adult bicondylar fracture. Because the fracture is distal, the fracture surfaces are broader than those proximally through the supracondylar fractures. This broader surface area of the fracture line may help prevent tilting of the distal fragment. Because the fracture lines do not involve the articular surface, development of joint incongruity with resultant loss of elbow motion is unlikely if malunion occurs. 
The distal humeral epiphysis extends across to include the secondary ossification of the medial epicondyle until about 6 to 7 years of age in girls and 8 to 9 years in boys. Thus, fractures involving the entire physeal line include the medial epicondyle up to this age. In older children, only the lateral and medial condylar physeal lines are included. 
Finally, part of the blood supply to the medial crista of the trochlea courses directly through the physis. The blood supply to this area is vulnerable to injury, which may cause osteonecrosis in this part of the trochlea. 
Because the physeal line is more proximal in young infants, it is nearer the center of the olecranon fossa (Fig. 20-6). A hyperextension injury in this age group is more likely to result in a physeal separation than a bony supracondylar fracture.14 
Figure 20-6
 
A: At 5 months of age, the metaphysis has advanced only to the supracondylar ridges. B: By 4 years of age, the edge of the metaphysis has advanced well into the area of the epicondyles.
A: At 5 months of age, the metaphysis has advanced only to the supracondylar ridges. B: By 4 years of age, the edge of the metaphysis has advanced well into the area of the epicondyles.
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Figure 20-6
A: At 5 months of age, the metaphysis has advanced only to the supracondylar ridges. B: By 4 years of age, the edge of the metaphysis has advanced well into the area of the epicondyles.
A: At 5 months of age, the metaphysis has advanced only to the supracondylar ridges. B: By 4 years of age, the edge of the metaphysis has advanced well into the area of the epicondyles.
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Treatment Options for Fractures Involving the Entire Distal Humerus

Treatment is first directed toward prompt injury recognition. Because this damage may be associated with child abuse, the parents may delay seeking treatment. The goal of treatment is to obtain acceptable alignment until the fracture heals over 2 to 3 weeks. 
Simple splint or cast immobilization has been suggested by several authors.4,17,46,59 In some small children, this may be the only treatment option that is reasonable. However, some investigators have shown cubitus varus after nonoperative treatment of these fractures.1,16,17,34 The rate of varus was noted in 3/12,17 15/21,1 and 5/734 in these series. De Jager and Hoffman16 reported 12 fracture separations of the distal humeral epiphysis, three of which were initially diagnosed as fractures of the lateral condyle and one as an elbow dislocation. Because of the frequency of cubitus varus after this injury in young children, they recommended closed reduction and percutaneous pinning in children younger than 2 years of age so that the carrying angle can be evaluated immediately after reduction and corrected if necessary. Arthrography may be helpful for diagnostic reasons and to assess reduction after fixation. 
Several investigators have reported open reduction, usually performed owing to misdiagnosis as a displaced fracture of the lateral humeral condyle.2,34,66,79 Mizuno et al.,53 however, recommended primary open reduction because of their poor results with closed reduction. They approached the fracture posteriorly by removing the triceps insertion from the olecranon with a small piece of cartilage. If the fracture is old (more than 5 to 6 days) and the epiphysis is no longer mobile, manipulation should not be attempted, and the elbow should be splinted for comfort. Many essentially untreated fractures remodel completely without any residual deformity if the distal fragment is only medially translocated and not tilted (Fig. 20-7). In the more displaced malunions, a later osteotomy may be indicated. 
Figure 20-7
Remodeling of untreated fractures.
 
A: AP view of a 2-year old who had an unrecognized and untreated fracture of the distal humeral physis. The medial translocation is apparent. There was no varus or valgus tilting. B: Four years later, there had been almost complete remodeling of the distal humerus. A small supracondylar prominence (arrow) remains as a scar from the original injury. C: Clinical appearance 4 years after injury shows no difference in elbow alignment.
A: AP view of a 2-year old who had an unrecognized and untreated fracture of the distal humeral physis. The medial translocation is apparent. There was no varus or valgus tilting. B: Four years later, there had been almost complete remodeling of the distal humerus. A small supracondylar prominence (arrow) remains as a scar from the original injury. C: Clinical appearance 4 years after injury shows no difference in elbow alignment.
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Figure 20-7
Remodeling of untreated fractures.
A: AP view of a 2-year old who had an unrecognized and untreated fracture of the distal humeral physis. The medial translocation is apparent. There was no varus or valgus tilting. B: Four years later, there had been almost complete remodeling of the distal humerus. A small supracondylar prominence (arrow) remains as a scar from the original injury. C: Clinical appearance 4 years after injury shows no difference in elbow alignment.
A: AP view of a 2-year old who had an unrecognized and untreated fracture of the distal humeral physis. The medial translocation is apparent. There was no varus or valgus tilting. B: Four years later, there had been almost complete remodeling of the distal humerus. A small supracondylar prominence (arrow) remains as a scar from the original injury. C: Clinical appearance 4 years after injury shows no difference in elbow alignment.
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Nonoperative Treatment of Fractures Involving the Entire Distal Humerus

Indications/Contraindications

In neonates and very small infants in whom general anesthesia or percutaneous pin fixation may be difficult, splint or cast immobilization can be used to treat these fractures (Table 20-1). 
Table 20-1
Nonoperative Treatment of Fractures Involving the Entire Distal Humerus
Indications Relative Contraindications
Neonate/small infants where anesthesia or pin fixation difficult Markedly displaced fractures with prompt diagnosis
Minimal displacement
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Techniques

The arm is simply immobilized in up to 90 degrees of flexion with the forearm pronated. The extremity is then externally stabilized with a swathe or figure-of-eight splint. 

Outcomes

Outcome and function is usually good, however some investigators have shown cubitus varus after nonoperative treatment of these fractures.1,16,17,34 The rate of varus was noted in 3/12,17 15/21,1 and 5/734 in these series. 

Operative Treatment of Fractures Involving the Entire Distal Humerus

Indications/Contraindications

In most infants and young children with a displaced fracture, external immobilization is usually not dependable in maintaining the reduction, and therefore operative intervention is indicated. 

Surgical Procedure

Closed reduction and percutaneous pin fixation. 
Preoperative Planning.
Planning is similar to that of treating a supracondylar humerus fracture. In cases where the elbow is largely unossified, one must prepare for possible arthrography to help with diagnosis and to assess reduction (Table 20-2). 
 
Table 20-2
ORIF of Fractures Involving the Entire Distal Humerus
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Table 20-2
ORIF of Fractures Involving the Entire Distal Humerus
Preoperative Planning Checklist
  •  
    OR Table: Regular OR table with C arm used as table vs. radiolucent table
  •  
    Position/positioning aids: Position on edge of bed with arm free over side if using C arm, position to opposite edge of table if using radiolucent table. In small infants, may need to position head and body on radiolucent table.
  •  
    Fluoroscopy location: Parallel to table from head or from below
  •  
    Equipment: K-wires or C wires
X
Positioning.
You can choose to position the patient in one of the two ways. You can position the patient on the edge of the table with the affected extremity free over the side of the table and use the base of the C-arm as the operative surface. Alternatively you can position the patient on a radiolucent table on the edge opposite of the affected extremity. The C-arm can be brought underneath the table so that you can use the radiolucent table as the operative surface rather than the C arm. In the very young, the head and body may also need to be on the radiolucent table. 
Technique.
Under general anesthesia, the elbow is initially manipulated while extension to correct the medial displacement, and then the fragment is stabilized by flexing the elbow and pronating the forearm. When the forearm is supinated with the elbow flexed, the distal fragment tends to displace medially. This displacement is usually a pure medial horizontal translocation without mediolateral coronal tilting. The fragment is secured with two lateral pins (Fig. 20-8). Because of the swelling and immaturity of the distal humerus, the medial epicondyle is difficult to define as a distinct landmark, making it risky to attempt the percutaneous placement of a medial pin. If a medial pin is necessary for stable fracture fixation, a small medial incision can be made to allow direct observation of the medial epicondyle and the ulnar nerve. Usually two or lateral small, smooth lateral pins are used. In small infants and young children with minimal ossification of the epiphyseal fragment, an intraoperative arthrogram may be obtained to help determine the quality of the reduction (Table 20-3). 
Figure 20-8
 
A: Injury film of a 20-month old showing medial displacement of the distal fragment. B, C: The medial and posterior displacement of the condylar fragment (arrows) is better defined after an arthrogram. D: Fixation is achieved by two lateral pins placed percutaneously.
A: Injury film of a 20-month old showing medial displacement of the distal fragment. B, C: The medial and posterior displacement of the condylar fragment (arrows) is better defined after an arthrogram. D: Fixation is achieved by two lateral pins placed percutaneously.
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Figure 20-8
A: Injury film of a 20-month old showing medial displacement of the distal fragment. B, C: The medial and posterior displacement of the condylar fragment (arrows) is better defined after an arthrogram. D: Fixation is achieved by two lateral pins placed percutaneously.
A: Injury film of a 20-month old showing medial displacement of the distal fragment. B, C: The medial and posterior displacement of the condylar fragment (arrows) is better defined after an arthrogram. D: Fixation is achieved by two lateral pins placed percutaneously.
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Table 20-3
Closed Reduction and Pinning of Fractures Involving the Entire Distal Humerus
Surgical Steps
  •  
    Assess arm under fluoroscopy
  •  
    In extension, correct medial or lateral displacement
  •  
    Flex elbow up while pronating arm
  •  
    Secure fracture with two divergent lateral pins
  •  
    If medial pin is needed for stability, make small incision over medial epicondyle and visualize directly, and pull back ulnar nerve to avoid injury
  •  
    If difficult to assess reduction, perform arthrogram to assess alignment. Arthrogram can be performed by injecting posteriorly into olecranon fossa or laterally into soft spot of elbow
  •  
    Bend and cut pins, and place xeroform and drain sponge under underneath pins
  •  
    Place well-padded bivalved long arm cast in comfortable amount of flexion (approximately 60–80 degrees)
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Author's Preferred Treatment for Fractures Involving the Entire Distal Humerus

In neonates and very small infants in whom general anesthesia or percutaneous pin fixation may be difficult, we typically simply immobilize the extremity in 90 degrees of flexion with the forearm pronated. The extremity is then externally stabilized with a figure-of-eight splint. 
In most older infants and young children, external immobilization is usually not dependable in maintaining the reduction. As a rule, in these patients, we perform the manipulation with the patient under general anesthesia and the fragment is secured with two lateral pins (Fig. 20-8). If a medial pin is necessary for stable fracture fixation, a small medial incision should be made. An intraoperative arthrogram may be obtained to help determine the quality of the reduction in patients with limited ossification. We have done similar surgery in neonates and very young children who can tolerate anesthesia safely. 
If treatment is delayed more than 3 to 5 days and if the epiphysis is not freely movable, the elbow is simply immobilized in a splint or cast. It is probably better to treat any resulting deformity later with a supracondylar osteotomy rather than to risk the complication of physeal injury or osteonecrosis of the epiphysis by performing a delayed manipulation or open reduction. Only occasionally does an untreated patient have a deformity severe enough to require surgical correction at a later date. Because the articular surface is intact, complete functional recovery can usually be expected. 

Postoperative Care

A cast or splint is maintained for 3 weeks. At 3 weeks, the patient's cast is removed, imaging is obtained, and the pins are removed in the office. The patient is discharged without immobilization and active elbow motion is resumed. The patient is then followed until full motion is regained and until there is radiographic evidence of normal physeal and epiphyseal growth. 

Potential Pitfalls and Preventative Measures

Because of the swelling and immaturity of the distal humerus, the ulnar nerve is at risk with placement of a medial pin. Making a small incision and by pulling ulnar nerve out of the way helps prevent iatrogenic injury. Quality of reduction is difficult to assess in small infants and young children and an intraoperative arthrogram can ensure adequate reduction (Table 20-4). 
 
Table 20-4
Fractures Involving the Entire Distal Humerus
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Table 20-4
Fractures Involving the Entire Distal Humerus
Potential Pitfalls and Preventions
Pitfalls Preventions
Use medial pin, inaccurate placement or iatrogenic ulnar nerve palsy Lateral entry pin placement
If medial pin absolutely needed, make small incision over medial epicondyle and visualize directly, pull ulnar nerve posteriorly with your finger
Difficulty gauging reduction because of elbow being largely unossified Perform arthrogram to assess reduction
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Management of Expected Adverse Outcomes and Unexpected Complications in Fractures Involving the Entire Distal Humerus

Malunion

Significant cubitus varus deformity can occur after this injury (Fig. 20-7C).46,50 Because the fracture surfaces are wider with this injury than with supracondylar fractures, the distal fragment tends to tilt less, which seems to account for the lower incidence of cubitus varus after this injury than after untreated supracondylar fractures; however, reduction and percutaneous pinning are recommended for acute fractures with displacement to prevent this complication. Late supracondylar humerus osteotomy may be indicated when there is insufficient remodeling. (See Chapter 16 for details of surgical techniques for osteotomies.) 

Neurovascular Injuries

Neurovascular injuries, either transient or permanent, are rare with this fracture. This is probably because the fracture fragments are covered with physeal cartilage and do not have sharp edges. In addition, the fracture fragments are usually not as markedly displaced as supracondylar humerus. Finally, the fracture displacement is usually posteromedial rather than posterolateral. 

Nonunion

Only one nonunion after this fracture has been reported; it occurred in a patient seen 3 months after the initial injury.53 Because of the extreme vascularity and propensity for osteogenesis in this area, union is rapid even in patients who receive essentially no treatment. 

Osteonecrosis

Osteonecrosis of the epiphysis of the lateral condyle or the trochlear epiphysis has rarely been reported after fractures of the entire distal humeral physis. Yoo et al.81 reported eight patients with osteonecrosis of the trochlea after fracture separations of the distal end of the humerus. Six of the eight fractures were diagnosed initially as medial condylar fractures, lateral condylar fractures, or traumatic elbow dislocation. All eight patients had rapid dissolution of the trochlea within 3 to 6 weeks after injury, followed by the development of a medial or central condylar fishtail defect. Further discussion regarding the etiology of this complication is discussed in the section on osteonecrosis of the trochlea (Table 20-5). 
 
Table 20-5
Fractures Involving the Entire Distal Humerus
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Table 20-5
Fractures Involving the Entire Distal Humerus
Common Adverse Outcomes and Complications
Malunion/cubitus varus
Neurovascular injuries (rare)
Osteonecrosis of lateral condyle or trochlear epiphysis (rare)
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Summary, Controversies, and Future Directions for Fractures Involving the Entire Distal Humerus

Transphyseal injuries of the distal humerus are rare. In young children, child abuse should be suspected and the patient should be evaluated for associated injuries. The injury should be distinguished from an elbow dislocation, which may be difficult in the unossified elbow. In neonates or children in which anesthesia is difficult, simple immobilization can be used, but patients may heal in varus. In children who can tolerate anesthesia, closed reduction and pin fixation can improve alignment and minimize complications of cubitus varus. An arthrogram may be needed to assess reduction. 

Introduction to Fractures Involving the Medial Condyle

Fractures of the medial condyle can be thought of as the mirror image of lateral condyle fractures, which are more commonly encountered (see Chapter 19). Fractures involving the medial condyle have two components. The intra-articular component involves, in some manner, the trochlear articular surface. The extra-articular portion includes the medial metaphysis and medial epicondyle. Because the fracture line extends into the articular surface of the trochlea, these often are called trochlear fractures. For purposes of description in this chapter, fractures of the trochlea are those that include only the articular surface. 
Fractures involving the medial condyle are rare in skeletally immature children, accounting for less than 1% of fractures involving the distal humerus.35 Many of the large series of elbow fractures in the literature and early fracture texts do not mention these fractures as a separate entity. Blount8 described only one such fracture in his classic text. In Faysse and Marion's21 review of more than 2,000 fractures of the distal humerus in children, only 10 fractures involved the medial condyle. Although it has been reported in a child as young as 2 years of age,3 this fracture pattern is generally considered to occur during later childhood. These rare injuries are very problematic as they can occur before the trochlear secondary center of ossification appears. A high index of suspicion is necessary to avoid missing a displaced, intra-articular fracture in the young (Fig. 20-9A, B). 
Figure 20-9
Intra-articular extension.
 
A: Injury film in a 7-year-old girl who was initially suspected of having only a fracture of the medial epicondyle. In addition to moderate displacement, there was a significant metaphyseal fragment (arrow). B: An arthrogram revealed intra-articular components (arrow), which defined this injury instead as a fracture involving the medial condylar physis.
 
(Courtesy of Carl McGarey, MD.)
A: Injury film in a 7-year-old girl who was initially suspected of having only a fracture of the medial epicondyle. In addition to moderate displacement, there was a significant metaphyseal fragment (arrow). B: An arthrogram revealed intra-articular components (arrow), which defined this injury instead as a fracture involving the medial condylar physis.
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Figure 20-9
Intra-articular extension.
A: Injury film in a 7-year-old girl who was initially suspected of having only a fracture of the medial epicondyle. In addition to moderate displacement, there was a significant metaphyseal fragment (arrow). B: An arthrogram revealed intra-articular components (arrow), which defined this injury instead as a fracture involving the medial condylar physis.
(Courtesy of Carl McGarey, MD.)
A: Injury film in a 7-year-old girl who was initially suspected of having only a fracture of the medial epicondyle. In addition to moderate displacement, there was a significant metaphyseal fragment (arrow). B: An arthrogram revealed intra-articular components (arrow), which defined this injury instead as a fracture involving the medial condylar physis.
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Most series21,60 show medial condylar fractures occurring somewhat later than lateral condylar fractures. A review of 38 patients in nine series3,12,13,20,21,24,28,60,65,78 in which the specific ages were given showed that 37 patients were in the age range of 8 to 14 years. Thus, this fracture seems to occur most often after the ossification centers of the medial condylar epiphysis begin to appear. As mentioned, a medial condylar fracture can occur as early as 6 months of age, however, before any ossification of the distal humerus has appeared,5,15 making the diagnosis extremely difficult and outcome poor if missed and not treated acutely. 

Assessment of Fractures Involving the Medial Condylar Physis

Mechanisms of Injury for Fractures Involving the Medial Condylar Physis

Two separate mechanisms can produce physeal fractures of the medial condyle. Ashurst's3 patients described falling directly on the point of the flexed elbow. This mechanism was also implicated in other reports.5,12,31,65 In this mechanism, it is speculated that the semilunar notch's sharp edge of the olecranon splits the trochlea directly (Fig. 20-10A). This mechanism is also supported by a recent case report of a medial condyle fracture in the setting of a pre-existing fishtail deformity.55 
Figure 20-10
Medial condylar fracture mechanisms of injury.
 
A: A direct force applied to the posterior aspect of the elbow causes the sharp articular margin of the olecranon to wedge the medial condyle from the distal humerus. B: Falling on the outstretched arm with the elbow extended and the wrist dorsiflexed causes the medial condyle to be avulsed by both ligamentous and muscular forces.
A: A direct force applied to the posterior aspect of the elbow causes the sharp articular margin of the olecranon to wedge the medial condyle from the distal humerus. B: Falling on the outstretched arm with the elbow extended and the wrist dorsiflexed causes the medial condyle to be avulsed by both ligamentous and muscular forces.
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A: A direct force applied to the posterior aspect of the elbow causes the sharp articular margin of the olecranon to wedge the medial condyle from the distal humerus. B: Falling on the outstretched arm with the elbow extended and the wrist dorsiflexed causes the medial condyle to be avulsed by both ligamentous and muscular forces.
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Figure 20-10
Medial condylar fracture mechanisms of injury.
A: A direct force applied to the posterior aspect of the elbow causes the sharp articular margin of the olecranon to wedge the medial condyle from the distal humerus. B: Falling on the outstretched arm with the elbow extended and the wrist dorsiflexed causes the medial condyle to be avulsed by both ligamentous and muscular forces.
A: A direct force applied to the posterior aspect of the elbow causes the sharp articular margin of the olecranon to wedge the medial condyle from the distal humerus. B: Falling on the outstretched arm with the elbow extended and the wrist dorsiflexed causes the medial condyle to be avulsed by both ligamentous and muscular forces.
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A: A direct force applied to the posterior aspect of the elbow causes the sharp articular margin of the olecranon to wedge the medial condyle from the distal humerus. B: Falling on the outstretched arm with the elbow extended and the wrist dorsiflexed causes the medial condyle to be avulsed by both ligamentous and muscular forces.
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In three more recent series,11,23,24 many patients sustained this injury when they fell on their outstretched arms. The theory is that this is an avulsion injury caused by a valgus strain at the elbow (Fig. 20-10B). Fowles and Kassab23 reported a patient with a concomitant valgus greenstick fracture of the olecranon associated with a fracture of the medial condyle. They believed this fracture provided further evidence that this was a valgus avulsion type of injury. Once the fragment becomes disassociated from the distal humerus, the forearm flexor muscles produce a sagittal anterior rotation of the fragment. 

Associated Injuries with Fractures Involving the Medial Condylar Physis

As this fracture is rare, studies describing associated injuries are rare. Medial condylar physeal fractures have been reported in association with greenstick fractures of the olecranon and with true posterolateral elbow dislocations (Fig. 20-11).5,15,23 Some investigators5,15 found that child abuse was more common in their younger patients with these fractures than with other elbow fractures. Regardless, the extremity should be evaluated for concomitant injuries of forearm, wrist, or hand, and the radiographs should be inspected for additional fractures about the elbow. 
Figure 20-11
A: (lateral) and (B) (AP) injury films of a 10-year-old girl who sustained a type III displaced fracture of the medial condyle associated with a posterolateral elbow dislocation.
(Part A Courtesy of Elizabeth A. Szalay, MD.)
(Part A Courtesy of Elizabeth A. Szalay, MD.)
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Signs and Symptoms of Fractures Involving the Medial Condylar Physis

Clinically and on radiographs, a fracture of the medial condylar physis is most often confused with a fracture of the medial epicondyle.41 In both types of intra- and extra-articular fractures, swelling is concentrated medially, and there may be valgus instability of the elbow joint. In a true intra-articular fracture, however, there is varus instability as well. Such is usually not the case with an isolated extra-articular fracture of the medial epicondyle. Ulnar nerve paresthesia may be present with both types of fractures. 

Imaging and Other Diagnostic Studies for Fractures Involving the Medial Condylar Physis

In older children with a large metaphyseal fragment, involvement of the entire condyle is usually obvious on radiographs (Fig. 20-12A); in younger children, in whom only the epicondyle is ossified, fracture of the medial condylar physis may be erroneously diagnosed as an isolated fracture of the medial epicondyle (Fig. 20-12B, C).13,20,23 
Figure 20-12
Missed medial condylar fracture.
 
A: Initial film of a 6-year old who was originally diagnosed as having a displaced fracture of the medial epicondyle (arrows). B: Normal side for comparison. C: Three months later, the patient continued to have a painful elbow, and there was ossification of the metaphysis (arrow) adjacent to the epicondyle.
A: Initial film of a 6-year old who was originally diagnosed as having a displaced fracture of the medial epicondyle (arrows). B: Normal side for comparison. C: Three months later, the patient continued to have a painful elbow, and there was ossification of the metaphysis (arrow) adjacent to the epicondyle.
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A: Initial film of a 6-year old who was originally diagnosed as having a displaced fracture of the medial epicondyle (arrows). B: Normal side for comparison. C: Three months later, the patient continued to have a painful elbow, and there was ossification of the metaphysis (arrow) adjacent to the epicondyle.
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Figure 20-12
Missed medial condylar fracture.
A: Initial film of a 6-year old who was originally diagnosed as having a displaced fracture of the medial epicondyle (arrows). B: Normal side for comparison. C: Three months later, the patient continued to have a painful elbow, and there was ossification of the metaphysis (arrow) adjacent to the epicondyle.
A: Initial film of a 6-year old who was originally diagnosed as having a displaced fracture of the medial epicondyle (arrows). B: Normal side for comparison. C: Three months later, the patient continued to have a painful elbow, and there was ossification of the metaphysis (arrow) adjacent to the epicondyle.
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A: Initial film of a 6-year old who was originally diagnosed as having a displaced fracture of the medial epicondyle (arrows). B: Normal side for comparison. C: Three months later, the patient continued to have a painful elbow, and there was ossification of the metaphysis (arrow) adjacent to the epicondyle.
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In differentiating these two fractures, it is helpful to remember that medial epicondylar fractures are often associated with elbow dislocations, usually posterolateral, and that elbow dislocations are rare before ossification of the medial condylar epiphysis begins. With medial condylar physeal fractures, the elbow tends to subluxate posteromedially13 because of the loss of trochlear stability. 
Any metaphyseal ossification with the epicondylar fragment suggests the presence of an intra-articular fracture of the medial condyle and is an indication for further evaluation. Often, the medial condyle and the medial epicondyle are markedly displaced as a unit. A positive fat pad sign indicates that the injury has entered the elbow joint and a fracture of the medial condyle is likely.31,71 Isolated fractures of the medial epicondyle are extra-articular and usually do not have positive fat pad signs. 
If the true location of the fracture line is questionable in a child younger than 8 to 10 years of age with significant medial elbow ecchymosis, arthrography or MRI of the elbow should be performed. 

Classification of Fractures Involving the Medial Condylar Physis

Classification, as with fractures of the lateral condylar physis, is based on the fracture line's location and the degree of the fracture's displacement. 

Location of the Fracture Line

Milch51 classified fractures of the medial condylar physis in adults into two types. In type I fractures, the fracture line traverses the apex of the trochlea. In type II fractures, it traverses more laterally through the capitulotrochlear groove. He believed that the origin of the fracture line depended on whether the radial head, as in type II, or the semilunar notch of the olecranon, as in type I, served as the impinging force for the abduction injury. Both fracture patterns occur in children (Fig. 20-13A), but type I fractures seem to be more common because the common physeal line, which serves as a point of weakness, ends in the apex of the trochlea. 
Figure 20-13
 
A: Medial condylar fracture patterns. In the Milch type I injury, the fracture line terminates in the trochlear notch (left, arrow). In the Milch type II injury, the fracture line terminates more laterally in the capitulotrochlear groove (right, arrow). (Adapted and reprinted with permission from Milch H. Fractures and fracture–dislocations of the humeral condyles. J Trauma. 1964;4:592–607.) B: Kilfoyle classification of displacement patterns. Degrees of displacement for fracture type I is an incomplete fracture that does not violate the joint but may hinge open; type II is a fracture that enters the joint but has less than 2 mm displacement; type III enters the joint and results in malangulation, malrotation, and articular displacement.
 
(Adapted and reprinted with permission from Kilfoyle RM. Fractures of the medial condyle and epicondyle of the elbow in children. Clin Orthop. 1965; 41:43–50.)
A: Medial condylar fracture patterns. In the Milch type I injury, the fracture line terminates in the trochlear notch (left, arrow). In the Milch type II injury, the fracture line terminates more laterally in the capitulotrochlear groove (right, arrow). (Adapted and reprinted with permission from 


Milch H. Fractures and fracture–dislocations of the humeral condyles. J Trauma. 1964;4:592–607.) B: Kilfoyle classification of displacement patterns. Degrees of displacement for fracture type I is an incomplete fracture that does not violate the joint but may hinge open; type II is a fracture that enters the joint but has less than 2 mm displacement; type III enters the joint and results in malangulation, malrotation, and articular displacement.
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Figure 20-13
A: Medial condylar fracture patterns. In the Milch type I injury, the fracture line terminates in the trochlear notch (left, arrow). In the Milch type II injury, the fracture line terminates more laterally in the capitulotrochlear groove (right, arrow). (Adapted and reprinted with permission from Milch H. Fractures and fracture–dislocations of the humeral condyles. J Trauma. 1964;4:592–607.) B: Kilfoyle classification of displacement patterns. Degrees of displacement for fracture type I is an incomplete fracture that does not violate the joint but may hinge open; type II is a fracture that enters the joint but has less than 2 mm displacement; type III enters the joint and results in malangulation, malrotation, and articular displacement.
(Adapted and reprinted with permission from Kilfoyle RM. Fractures of the medial condyle and epicondyle of the elbow in children. Clin Orthop. 1965; 41:43–50.)
A: Medial condylar fracture patterns. In the Milch type I injury, the fracture line terminates in the trochlear notch (left, arrow). In the Milch type II injury, the fracture line terminates more laterally in the capitulotrochlear groove (right, arrow). (Adapted and reprinted with permission from 


Milch H. Fractures and fracture–dislocations of the humeral condyles. J Trauma. 1964;4:592–607.) B: Kilfoyle classification of displacement patterns. Degrees of displacement for fracture type I is an incomplete fracture that does not violate the joint but may hinge open; type II is a fracture that enters the joint but has less than 2 mm displacement; type III enters the joint and results in malangulation, malrotation, and articular displacement.
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Displacement of the Fracture

Kilfoyle39 described three fracture displacement patterns that can be helpful in determining appropriate treatment (Fig. 20-13B). In type I, the fracture line in the medial condylar metaphysis extends down to the physis. He noted that some of these might represent incomplete supracondylar fractures. Unless there is a greenstick crushing of the medial supracondylar column, these fractures are usually of no clinical significance. In type II, the fracture line extends into the medial condylar physis. The intra-articular portion, as it is in preosseous cartilage, is often not recognized. In this second type, the medial condylar fragment usually remains undisplaced. In type III, the condylar fragment is both rotated and displaced. Some authors use a modification of Kilfoyle's classification based on amount of displacement and describe it as nondisplaced (<2 mm), minimally displaced (2 to 4 mm), and displaced (>4 mm).77 Bensahel et al.5 and Papavasiliou et al.60 found that type III displacement fractures, which accounted for only 25%, were more likely to occur in older adolescents, and type I fractures were more common in younger children. These studies also confirmed the correlation between the type of displacement and the treatment method. 

Pathoanatomy and Applied Anatomy Relating to Fractures Involving the Medial Condylar Physis

Fractures of the medial condylar physis involve both intra- and extra-articular components. They behave as Salter–Harris type IV physeal injuries, but not enough fractures have been described to show whether the fracture line courses through the secondary ossification center of the medial condylar epiphysis or whether it enters the common physeal line separating the lateral condylar ossification center from the medial condylar ossification center. This common physeal line terminates in the notch of the trochlea. The trochlea's lateral crista is ossified from the lateral condylar epiphysis. Only the medial crista is ossified by the secondary ossification centers of the medial condylar epiphysis. We believe that this fracture is a “mirror image” of the lateral condylar physeal injury and thus has characteristics of Salter–Harris type IV physeal injuries (Fig. 20-14). The deformity that develops if the fracture is untreated is nonunion, similar to that after lateral condylar physeal fracture, rather than physeal fusion, as occurs after a typical Salter–Harris type IV injury. The resultant deformity of a medial condylar nonunion is cubitus varus instead of the cubitus valgus deformity that occurs with nonunion of the lateral condyle. 
Figure 20-14
 
A: The AP radiograph of a 9-year-old boy demonstrates the location of the ossification centers. A common physeal line (arrow) separates the medial and lateral condylar physes. B: Relationship of the ossification centers to the articular surface. The common physis terminates in the trochlear notch (arrow). C: Location of the usual fracture line involving the medial condylar physis (arrows).
A: The AP radiograph of a 9-year-old boy demonstrates the location of the ossification centers. A common physeal line (arrow) separates the medial and lateral condylar physes. B: Relationship of the ossification centers to the articular surface. The common physis terminates in the trochlear notch (arrow). C: Location of the usual fracture line involving the medial condylar physis (arrows).
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Figure 20-14
A: The AP radiograph of a 9-year-old boy demonstrates the location of the ossification centers. A common physeal line (arrow) separates the medial and lateral condylar physes. B: Relationship of the ossification centers to the articular surface. The common physis terminates in the trochlear notch (arrow). C: Location of the usual fracture line involving the medial condylar physis (arrows).
A: The AP radiograph of a 9-year-old boy demonstrates the location of the ossification centers. A common physeal line (arrow) separates the medial and lateral condylar physes. B: Relationship of the ossification centers to the articular surface. The common physis terminates in the trochlear notch (arrow). C: Location of the usual fracture line involving the medial condylar physis (arrows).
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Characteristically, the metaphyseal fragment includes the intact medial epicondyle along with the common flexor origin of the muscles of the forearm. These flexor muscles cause the loosened fragment to rotate so that the fracture surface is facing anteriorly and medially and the articular surface is facing posteriorly and laterally (Fig. 20-15).3,12 Rotation of the fragment is especially accentuated when the elbow is extended. Chacha12 also noted that often the lateral aspect of the common flexor origin and the anterior capsule of the joint were torn and the fracture surface could usually be reached through this anterior opening into the joint. 
Figure 20-15
Displacement of the medial condyle.
 
The pull of the forearm flexor muscles rotates the fragment so that the fracture surface is facing anteromedially and the articular surface is posterolateral.
 
(Adapted and reprinted with permission from Chacha PB. Fractures of the medial condyle of the humerus with rotational displacement. J Bone Joint Surg Am. 1970; 52:1453–1458.)
The pull of the forearm flexor muscles rotates the fragment so that the fracture surface is facing anteromedially and the articular surface is posterolateral.
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Figure 20-15
Displacement of the medial condyle.
The pull of the forearm flexor muscles rotates the fragment so that the fracture surface is facing anteromedially and the articular surface is posterolateral.
(Adapted and reprinted with permission from Chacha PB. Fractures of the medial condyle of the humerus with rotational displacement. J Bone Joint Surg Am. 1970; 52:1453–1458.)
The pull of the forearm flexor muscles rotates the fragment so that the fracture surface is facing anteromedially and the articular surface is posterolateral.
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The blood supply to the medial epicondyle and medial metaphysis courses extra-articularly along with the medial flexor muscle groups. The blood supply to the lateral ossification center of the medial crista of the trochlea, however, must traverse the surface of the medial condylar physis. If the fracture line disrupts these small intra-articular vessels, disruption and subsequent circulation loss to the lateral portion of the medial crista can result, leading to the development of a fishtail deformity. 

Treatment Options for Fractures Involving the Medial Condylar Physis

In Kilfoyle's displacement types I and II fracture patterns, enough residual internal stability is usually present to allow the fracture to be simply immobilized in a cast or posterior splint.5,21,25,39,60 As with fractures of the lateral condylar physis, union may be slow. In fractures treated promptly, results have been satisfactory.12,20,23 Because there is usually more displacement in older children, the results in this age group are not as satisfactory as those in younger children, who tend to have relatively nondisplaced fractures.5 
For displaced fractures, open reduction with internal fixation is the most often used treatment method.5,11,23,24,39,60,63,65 The fracture fragment can be approached by a posteromedial incision that allows good exposure of both the fracture site and the ulnar nerve. Fixation is easily achieved with smooth K-wires or with screws in older adolescents (Fig. 20-16A, B). Two wires are necessary because of the sagittal rotation forces exerted on the fracture fragment by the common flexor muscles. El Ghawabi24 reported frequent delayed union and nonunion in fractures that were not rigidly stabilized. 
Figure 20-16
 
A: Medial condyle fracture in an adolescent fixed with wires. B: Medial condyle fracture fixed with cannulated screws to allow early range of motion.
A: Medial condyle fracture in an adolescent fixed with wires. B: Medial condyle fracture fixed with cannulated screws to allow early range of motion.
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Figure 20-16
A: Medial condyle fracture in an adolescent fixed with wires. B: Medial condyle fracture fixed with cannulated screws to allow early range of motion.
A: Medial condyle fracture in an adolescent fixed with wires. B: Medial condyle fracture fixed with cannulated screws to allow early range of motion.
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Nonoperative Treatment of Fractures Involving the Medial Condylar Physis

Indications/Contraindications

Nondisplaced or minimally displaced fractures (Kilfoyle types I and II) can be treated nonoperatively with either splint or cast immobilization (Table 20-6). 
 
Table 20-6
Medial Condyle Fractures
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Table 20-6
Medial Condyle Fractures
Nonoperative Treatment
Indications Relative Contraindications
Nondisplaced fractures (Kilfoyle type I) Displaced fractures (Kilfoyle type III)
Minimally displaced fractures (some) (Kilfoyle type II)
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Operative Treatment of Fractures Involving the Medial Condylar Physis

Indications/Contraindications

For displaced fractures (Kilfoyle type III) operative fixation is recommended, as well as minimally displaced fractures (Kilfoyle type II) that demonstrate instability and/or progressive displacement. 

Surgical Procedure

Open reduction internal fixation of medial condyle fracture. 
Preoperative Planning. Adequate radiographs including oblique radiographs should be obtained to assess fracture morphology (Table 20-7). 
 
Table 20-7
ORIF of Fractures Involving the Medial Condylar Physis
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Table 20-7
ORIF of Fractures Involving the Medial Condylar Physis
Preoperative Planning Checklist
  •  
    OR Table:
  •  
    Position/positioning aids: Supine
  •  
    Fluoroscopy location: From head of bed under hand table
  •  
    Equipment: K-wires, cannulated screws (for patients near skeletal maturity)
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Positioning. Although medial epicondyle fractures may be approached supine or prone,26 typically the patient is positioned supine to approach a medial condyle fracture. You attach a hand table on the affected side. The arm can be externally rotated through the shoulder to access the medial condyle, and the elbow is flexed to relax the flexor mass. 
Surgical Approach. A posteromedial approach to the elbow is used that allows good exposure of both the fracture site and the ulnar nerve. 
Technique. An incision is centered over the medial condyle/epicondyle. Often there is significant soft tissue swelling and displacement. Dissection is carefully carried out to the level of the bony condyle and usually the fracture hematoma is quickly encountered. The medial brachial and antebrachial cutaneous nerves that transverse the field are protected. Care in the dissection avoids injury to the ulnar nerve, which sits posterior to the fragment but may be displaced by the fracture. The ulnar nerve is identified and protected to ensure that it is not entrapped in the reduced fracture and it is not iatrogenically injured by a fixation pin or screw. The fracture is cleared out of hematoma. The entire fracture line and joint surface should be identified to ensure accurate reduction of the joint surface. The fracture is reduced. In the supine position this requires flexion of the elbow and wrist with pronation of the forearm, which takes tension off of the condyle. The condyle is held in place, and K-wires are passed in a divergent manner to hold the fracture in place. Alternatively cannulated screws or a plate can be used in older patients near skeletal maturity to allow more rigid fixation and early motion (Table 20-8). 
 
Table 20-8
ORIF of Fractures Involving the Medial Condyle
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Table 20-8
ORIF of Fractures Involving the Medial Condyle
Surgical Steps
  •  
    Posteromedial incision over medial condyle
  •  
    Identify and protect ulnar nerve
  •  
    Clean fracture hematoma and identify fracture and joint surface
  •  
    Reduce fracture by taking tension of flexor mass by flexing elbow and wrist and pronating forearm
  •  
    Reduce joint and fracture
  •  
    Stabilize fracture with divergent K-wires (cannulated screws in older patients/adolescents)
  •  
    Apply bivalved long arm cast
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Author's Preferred Treatment for Fractures Involving The Medial Condylar Physis

We generally treat Kilfoyle type I nondisplaced fractures with simple observation and a posterior splint or long arm cast. Follow-up radiographs at weekly intervals are taken to ensure there is no late displacement. When there is good callus at the metaphyseal portion of the fracture line by 3 to 4 weeks, the splint is removed and early active motion is initiated. We continue to follow the patient until there is a full range of motion and obliteration of the fracture line. Some type II fractures that maintain alignment can also be treated nonoperatively; however, careful follow-up on weekly intervals are required to document that the fragment has not moved. 
Unstable Kilfoyle type II and type III displaced fractures must be reduced and stabilized. This is usually difficult to do by closed methods because the swelling associated with this injury makes it hard to accurately identify the landmarks for pin placement. We proceed with an open reduction through a medial approach with identification and protection of the ulnar nerve. The posterior surface of the condylar fragment and the medial aspect of the medial crista of the trochlea should be avoided in the dissection because these are the blood supply sources to the ossific nuclei of the trochlea. Fixation with two parallel pins should be in the metaphyseal segment if possible. We prefer cannulated screw fixation in adolescents near skeletal maturity to allow early protected range of motion. 

Postoperative Care

Patients will be immobilized largely dependent upon age, fracture pattern, and type of fixation. Nonoperatively treated fractures may be casted for 4 to 6 weeks, in a similar fashion to the treatment of lateral condyle fractures based on age, displacement, and amount of healing. Those treated with pin fixation similarly will be casted for 4 to 6 weeks depending on healing, and the pins are often removed at 4 weeks if exposed, and can be removed any time after 6 weeks if buried. In patients treated with more rigid fixation, early (10 to 14 days) transition to a hinged elbow brace with protected range of motion is recommended. 

Potential Pitfalls and Preventative Measures

Nondisplaced or minimally displaced fractures should be monitored closely to ensure that progressive displacement does not occur, which could lead to delayed union or nonunion. When treating patients operatively, the posterior surface of the condylar fragment and the medial aspect of the medial crista of the trochlea should be avoided in the dissection because these are the blood supply sources to the ossific nuclei of the trochlea. The ulnar nerve should be identified to avoid iatrogenic injury (Table 20-9). 
 
Table 20-9
Fractures Involving the Medial Condylar Physis
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Table 20-9
Fractures Involving the Medial Condylar Physis
Potential Pitfalls and Preventions
Pitfalls Preventions
Progressive displacement of minimally displaced fracture leading to delayed union Monitor fractures treated nonoperatively with careful radiographic follow-up
Disruption of blood supply leading to osteonecrosis Avoid dissection posteriorly on the fragment on the medial aspect of the medial crista of the trochlea
Iatrogenic ulnar nerve injury Perform adequate exposure to identify and protect ulnar nerve during reduction and pin fixation
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Management of Expected Adverse Outcomes and Unexpected Complications in Fractures Involving the Medial Condylar Physis

The major complication is failure to make the proper diagnosis. This is especially true in younger children, in whom a medial condylar fracture can be confused with a displaced fracture of the medial epicondyle (Fig. 20-12). When the diagnosis is a real possibility, especially in a child with no ossification of the trochlea, examination with anesthesia, arthrography, and/or MRI is required (Fig. 20-9). Leet et al.42 reported complications after 33% of 21 medial condylar fractures, including osteonecrosis of the trochlea, nonunion, and loss of reduction. Untreated displaced fractures usually result in nonunion with cubitus varus deformity (Fig. 20-17).23,78 These patients are at high risk for loss of motion, function, pain, and eventual arthrosis. Ryu et al.68 described a painful nonunion of the medial condyle in an adolescent that apparently resulted from a fracture when he was 3 years old. An osteotomy was made to remove the nonunited section of bone, and an iliac bone graft was inserted and fixed with two malleolar screws. Union was obtained, and the patient was able to participate in sports without pain. Delayed union has been reported in patients treated with insecure fixation or simply placed in a cast.24,39 
Figure 20-17
Nonunion in addition to cubitus varus deformity.
 
A: Original film of a 5-year-old girl who sustained an injury 1 year previously. The metaphyseal fragment (arrow) is attached to the medial epicondyle. B: Film taken 2 years later. Some ossification has developed in the medial condylar epiphysis (arrow).
 
(Courtesy of Roy N. Davis, MD.)
A: Original film of a 5-year-old girl who sustained an injury 1 year previously. The metaphyseal fragment (arrow) is attached to the medial epicondyle. B: Film taken 2 years later. Some ossification has developed in the medial condylar epiphysis (arrow).
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Figure 20-17
Nonunion in addition to cubitus varus deformity.
A: Original film of a 5-year-old girl who sustained an injury 1 year previously. The metaphyseal fragment (arrow) is attached to the medial epicondyle. B: Film taken 2 years later. Some ossification has developed in the medial condylar epiphysis (arrow).
(Courtesy of Roy N. Davis, MD.)
A: Original film of a 5-year-old girl who sustained an injury 1 year previously. The metaphyseal fragment (arrow) is attached to the medial epicondyle. B: Film taken 2 years later. Some ossification has developed in the medial condylar epiphysis (arrow).
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Some disturbance of the vascular supply to the medial condylar fragment may occur during open reduction and internal fixation or at the time of initial injury. Several investigators have reported subsequent avascular changes in the medial crista of the trochlea.23,24,39,60 Hanspal28 reviewed Cothay's original patient13 18 years after delayed open reduction and found that despite some minimal loss of motion, the patient was asymptomatic. Radiographs, however, showed changes compatible with osteonecrosis of the medial condyle. 
Both cubitus varus and valgus deformities have been reported in patients whose fractures united uneventfully. The valgus deformity appears to be caused by secondary stimulation or overgrowth of the medial condylar fragment. Some simple stimulation of the medial epicondyle's prominence may also produce the false appearance of a cubitus valgus deformity. Cubitus varus appears to result from decreased growth of the trochlea, possibly caused by a vascular insult. Principles for treating nonunion of lateral condylar fractures are generally applicable to nonunions of the medial condyle (Fig. 20-18). 
Figure 20-18
Nonunion of a medial condylar fracture in a 10-year-old girl.
 
Note medial subluxation of the radius and ulna. compression screws. Lateral radiograph of capitellar shear fracture treated with anterior to posterior headless compression screws.
Note medial subluxation of the radius and ulna. compression screws. Lateral radiograph of capitellar shear fracture treated with anterior to posterior headless compression screws.
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Figure 20-18
Nonunion of a medial condylar fracture in a 10-year-old girl.
Note medial subluxation of the radius and ulna. compression screws. Lateral radiograph of capitellar shear fracture treated with anterior to posterior headless compression screws.
Note medial subluxation of the radius and ulna. compression screws. Lateral radiograph of capitellar shear fracture treated with anterior to posterior headless compression screws.
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El Ghawabi24 described one partial ulnar neuropathy occurring after this type of injury. The neuropathy almost completely recovered after anterior transposition of the ulnar nerve (Table 20-10). 
 
Table 20-10
Fractures Involving the Medial Condylar Physis
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Table 20-10
Fractures Involving the Medial Condylar Physis
Common Adverse Outcomes and Complications
Stiffness
Ulnar neuropathy
Delayed union
Nonunion
Cubitus varus
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Summary, Controversies, and Future Directions in Fractures Involving the Medial Condylar Physis

Medial condyle fractures are rare. The key is identifying them and making the proper diagnosis. The classification, radiographic assessment, and treatment goals are similar to lateral condyle fractures which are encountered much more commonly. Although nondisplaced or minimally displaced fractures can be treated nonoperatively in a cast, careful monitoring is required to identify further displacement and delayed union. When displaced, open treatment with identification of the ulnar nerve and direct visualization of the joint surface is needed. The rate of complications is relatively high and may include osteonecrosis, elbow stiffness, malunion, or delayed union. 

Introduction to Fractures Involving the Lateral Epicondylar Apophysis

Fracture of the lateral epicondylar apophysis is a rare injury, with only a few isolated injuries described, mostly in textbooks.32,47,70,75 In a review of 5,228 fractures of the distal humerus, Chambers and Wilkins identified one fracture of the lateral epicondyle.70 

Assessment of Fractures Involving the Lateral Epicondylar Apophysis

Mechanisms of Injury for Fractures Involving the Lateral Epicondylar Apophysis

In adults, the most common etiology is that of a direct blow to the lateral side of the elbow. In children, because the forearm extensor muscles originate from this area, it is believed that avulsion forces from these muscles can be responsible for some of these injuries. Hasner and Husby32 suggested that the location of the fracture line in relation to the origins of the various extensor muscles determines the degree of displacement that can occur (Fig. 20-19). If the proximal part of the fracture line lies between the origin of the common extensors and the extensor carpi radialis longus, there is usually little displacement. If the fracture lines enter the area of origin of the extensor carpi radialis longus, then considerable displacement can occur. 
Figure 20-19
Soft tissue attachments.
 
The origins of the forearm and wrist extensor muscles, radial collateral ligament, and outline of the capsule are shown in relation to the lateral epicondylar apophysis.
 
(From Hasner E, Husby J. Fracture of the epicondyle and condyle of humerus. Acta Chir Scand. 1951; 101:195–202, with permission.)
The origins of the forearm and wrist extensor muscles, radial collateral ligament, and outline of the capsule are shown in relation to the lateral epicondylar apophysis.
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Figure 20-19
Soft tissue attachments.
The origins of the forearm and wrist extensor muscles, radial collateral ligament, and outline of the capsule are shown in relation to the lateral epicondylar apophysis.
(From Hasner E, Husby J. Fracture of the epicondyle and condyle of humerus. Acta Chir Scand. 1951; 101:195–202, with permission.)
The origins of the forearm and wrist extensor muscles, radial collateral ligament, and outline of the capsule are shown in relation to the lateral epicondylar apophysis.
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Associated Injuries with Fractures Involving the Lateral Epicondylar Apophysis

As this fracture is so rare, associated injuries are not well described. 

Signs and Symptoms of Fractures Involving the Lateral Epicondylar Apophysis

Patients will present similar to other elbow fractures, with pain and swelling in the elbow, with pain often localized to the lateral aspect of the distal humerus. 

Imaging and Other Diagnostic Studies for Fractures Involving the Lateral Epicondylar Apophysis

Fractures can often be confused with normal anatomy of the lateral epicondyle.70 The distal part of the epiphysis fuses with the capitellum before the proximal part unites with the adjacent humerus. This frequently results in the physis appearing like a fracture. Also, ossification of the epiphysis begins at the level of the capitellar physis and proceeds first to a typical sliver shape and then to a triangular shape. This natural separation can be confused with an avulsion fracture.70 The key to determining true separation is looking beyond the osseous tissues for the presence of associated soft tissue swelling (Fig. 20-20). If the ossification center lies distal to the osteochondral border of the lateral condylar epiphysis, it should be considered displaced (Fig. 20-21). Comparing radiographs of the contralateral elbow can be used to aid in diagnosis. 
Figure 20-20
Lateral swelling.
 
A: Soft tissue swelling in the area of the lateral epicondylar apophysis (arrows) suggests an undisplaced fracture involving the apophysis. The fragmentation of the apophysis is caused by irregular ossification. B: A small avulsion of the lateral epicondyle (open arrow) in an adolescent who is almost skeletally mature. There was considerable soft tissue swelling in this area (solid arrows).
A: Soft tissue swelling in the area of the lateral epicondylar apophysis (arrows) suggests an undisplaced fracture involving the apophysis. The fragmentation of the apophysis is caused by irregular ossification. B: A small avulsion of the lateral epicondyle (open arrow) in an adolescent who is almost skeletally mature. There was considerable soft tissue swelling in this area (solid arrows).
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Figure 20-20
Lateral swelling.
A: Soft tissue swelling in the area of the lateral epicondylar apophysis (arrows) suggests an undisplaced fracture involving the apophysis. The fragmentation of the apophysis is caused by irregular ossification. B: A small avulsion of the lateral epicondyle (open arrow) in an adolescent who is almost skeletally mature. There was considerable soft tissue swelling in this area (solid arrows).
A: Soft tissue swelling in the area of the lateral epicondylar apophysis (arrows) suggests an undisplaced fracture involving the apophysis. The fragmentation of the apophysis is caused by irregular ossification. B: A small avulsion of the lateral epicondyle (open arrow) in an adolescent who is almost skeletally mature. There was considerable soft tissue swelling in this area (solid arrows).
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Figure 20-21
Avulsion injury.
 
A: Avulsion of a portion of the lateral epicondyle in an adolescent (arrow). B: The appearance 9 months later shows fragmentation and partial union of the fragment.
 
(Courtesy of R. Chandrasekharan, MD.)
A: Avulsion of a portion of the lateral epicondyle in an adolescent (arrow). B: The appearance 9 months later shows fragmentation and partial union of the fragment.
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Figure 20-21
Avulsion injury.
A: Avulsion of a portion of the lateral epicondyle in an adolescent (arrow). B: The appearance 9 months later shows fragmentation and partial union of the fragment.
(Courtesy of R. Chandrasekharan, MD.)
A: Avulsion of a portion of the lateral epicondyle in an adolescent (arrow). B: The appearance 9 months later shows fragmentation and partial union of the fragment.
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Pathoanatomy and Applied Anatomy Relating to Fractures Involving the Lateral Epicondylar Apophysis

Because the presence of the lateral epicondylar apophysis is often misinterpreted as a small chip fracture, a thorough understanding of the anatomy and ossification process is essential for evaluating injuries in this area and distinguishing normal from pathoanatomy. 

Late Ossification.

The lateral epicondylar apophysis is present for a considerable period but does not become ossified until the second decade. The best discussion of the anatomy of the ossification process is in a report by Silberstein et al.,70 and much of the following discussion is paraphrased from their work. Just before ossification of the apophysis, the ossification margin of the lateral supracondylar ridge of the distal metaphysis curves abruptly medially toward the lateral condylar physis (Fig. 20-22). This process causes the osseous borders on the lateral aspect of the distal humerus to take the shape of the number 3. The central wedge of this defect contains the cartilaginous lateral epicondylar apophysis, which begins to ossify around 10 to 11 years of age. Ossification begins at the level of the lateral condylar physeal line and proceeds proximally and distally to form a triangle, with the apex directed toward the physeal line. The shape of the epicondylar apophyseal ossification center may also be in the form of a long sliver of bone with an irregular ossification pattern. Silberstein et al.70 noted that the fracture line involving the lateral condylar physis often involves the proximal physeal line of the lateral epicondylar apophysis. Thus, this apophysis is almost always included with the lateral condylar fragment. 
Figure 20-22
Lateral epicondylar apophysis.
 
A: The cartilaginous apophysis occupies the wedge-shaped defect at the margin of the lateral condyle and metaphysis (arrow). The dotted line shows the margin of the cartilaginous apophysis. B: Ossification of the apophysis begins at the central portion of the wedge defect (solid arrow) and progresses both proximally and distally (open arrows) to form a triangular center.
A: The cartilaginous apophysis occupies the wedge-shaped defect at the margin of the lateral condyle and metaphysis (arrow). The dotted line shows the margin of the cartilaginous apophysis. B: Ossification of the apophysis begins at the central portion of the wedge defect (solid arrow) and progresses both proximally and distally (open arrows) to form a triangular center.
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Figure 20-22
Lateral epicondylar apophysis.
A: The cartilaginous apophysis occupies the wedge-shaped defect at the margin of the lateral condyle and metaphysis (arrow). The dotted line shows the margin of the cartilaginous apophysis. B: Ossification of the apophysis begins at the central portion of the wedge defect (solid arrow) and progresses both proximally and distally (open arrows) to form a triangular center.
A: The cartilaginous apophysis occupies the wedge-shaped defect at the margin of the lateral condyle and metaphysis (arrow). The dotted line shows the margin of the cartilaginous apophysis. B: Ossification of the apophysis begins at the central portion of the wedge defect (solid arrow) and progresses both proximally and distally (open arrows) to form a triangular center.
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Treatment Options for Fractures Involving the Lateral Epicondylar Apophysis

Unless the fragment is incarcerated within the joint,47 treatment usually consists of simple immobilization for comfort. Although nonunion of the fragment can occur, this radiographic finding usually does not affect elbow function. There are lateral column osteochondral nonunions that represent chronic lateral ligament instability. Those patients are symptomatic, have functional limitations, and benefit from open repair. 

Management of Expected Adverse Outcomes and Unexpected Complications in Fractures Involving the Lateral Epicondylar Apophysis

Only one rare major complication has been described with fractures involving the lateral epicondylar apophysis: Entrapment of the fragment, either within the elbow joint47 or between the capitellum and the radial head.22 

Summary, Controversies, and Future Directions Related to Fractures Involving the Lateral Epicondylar Apophysis

Fractures of the lateral epicondyle are extremely rare. The radiographic appearance of the lateral epicondyle during growth can be confused with what appears to be a fracture. Unless there is entrapment in the joint, treatment is nonoperative. 

Fractures Involving the Trochlea

Osteochondral fractures involving only the articular portion of the trochlea are extremely rare in skeletally immature children. Grant and Miller27 reported a 13-year-old boy who had a posterolateral dislocation of the elbow with marked valgus instability and fractures of the medial epicondyle and radial neck. When the elbow was explored to secure the epicondyle, a large osteochondral fragment from the medial crista of the trochlea was found lying between the two articular surfaces. The fragment was replaced and fixed, and a satisfactory result was obtained, although the presence of the fragment was not detected preoperatively. 
Patel and Weiner61 described osteochondritis dissecans (OCD) in two patients (three elbows) aged 12 and 14 years. In one patient, open biopsy was done because the osteochondral lesion was thought to be a neoplastic lesion. The other patient with bilateral lesions was treated conservatively with good results. Matsuura et al.44 evaluated 1,802 young baseball players, 717 (40%) of whom had elbow pain. Of the 150 who had bilateral elbow radiographic examination, osteochondral lesions of the elbow were identified in 121 (81%); trochlear lesions accounted for 0.5% of these. More recently, Marshall et al.43 reported osteochondral lesions of the trochlea in 18 young athletes ranging in age from 6 to 17 years; 10 of the 18 were throwing athletes and two were gymnasts. Based on MRI and MR arthrogram findings, injuries were classified as chondral/osteochondral injury/OCD lesions (13 patients) or trochlear osteonecrosis (five patients). Ten of the 13 osteochondral lesions involved the lateral trochlea and were described as classic OCD; the three medial trochlear lesions were small (<6 mm) and were located on the posterior articular surface of the medial trochlea. Trochlear osteonecrosis in five patients was characterized by growth disturbance involving the ossification centers of the trochlea. The affected trochleas were misshapen and underdeveloped, and radiographs showed the secondary ossification centers to be fragmented, small, and sclerotic, or absent entirely. All five of the patients with osteonecrosis had histories of distal humeral fractures treated with K-wire fixation earlier in childhood (two lateral condylar fractures and one each supracondylar, medial epicondylar, and medial condylar fracture). The authors suggested that the athletic demands placed on the adolescent elbow revealed osteonecrosis from these earlier fractures.43 The OCD lesions consistently occurred in the posteroinferior aspect of the lateral trochlea corresponding to a watershed zone of diminished vascularity, and the authors hypothesized that the lesions were caused by repeated forced elbow extension/hyperextension that led to impingement of the normal blood supply.43 Small osteochondral lesions on the posteromedial trochlea were suggested to result from olecranon abutment occurring in an elbow with collateral ligament laxity or insufficiency. 
In an older child who sustains an elbow dislocation and in whom there is some widening of the joint after reduction, an intra-articular osteochondral or chondral fracture of the trochlea, capitellum, or radial head should be suspected. Arthrography, MRI, or computed tomography–arthrography, should be used for confirmation. 

Osteonecrosis of the Trochlea

Incidence

Toniolo and Wilkins76 reported a series of 30 cases collected over the past 20 years from various sources and suggested that osteonecrosis of the trochlea is probably one of the most unrecognized sequela of injuries to the distal humerus. Because avascular necrosis of the trochlea is rare, or often unrecognized, the true incidence is unknown. Bronfen reported six cases in 288 displaced supracondylar humerus fractures.10 McDonnell and Wilson reported four cases in a series of 53 supracondylar humerus fractures.45 We recently examined 15 cases of osteonecrosis of the trochlea, and during the same time period, greater than 3,500 patients were treated operatively for a supracondylar or humeral condylar fracture at our institution.25 This gives an incidence of less than 0.5% and does not include fractures treated nonoperatively, although some mild osteonecrosis cases may have been missed. 

Etiology

Three theories have been proposed to account for the posttraumatic changes that occur in the distal humerus after fractures in the vicinity of the trochlea: Malunion, partial growth arrest, and vascular injury. The most common form follows some type of elbow trauma. In some cases, the trauma is occult or poorly defined.7,37,45,48,54,81 It can occur after displaced or minimally displaced supracondylar humerus fractures, lateral condylar fractures, physeal separations, or medial condylar fractures, or may occur iatrogenically from excessive soft tissue stripping during operative exposure.57,76 Posttraumatic trochlear osteonecrosis results in a spectrum from simply a small defect of the trochlea (fishtail deformity) to complete destruction of the medial aspect of the distal humerus with a progressive varus deformity, decreased range of motion, and associated instability of the elbow. 

Vascular Anatomy

In Haraldsson's classic studies29,30 of the blood supply of the distal humerus, it was demonstrated that the medial crista of the trochlea had two separate blood supply sources (Fig. 20-23). Neither has anastomoses with each other or with the other metaphyseal vessels. In the young infant, the vessels are small and lie on the surface of the perichondrium. 
Figure 20-23
Blood supply of the trochlea.
 
A: Intraosseus vasculature in a 3-year-old boy. Only two small vessels supply the medial crista of the trochlea (arrows). The central portion of the crista appears avascular. B: In the lateral view through the medial crista of the trochlea, note that the vessels penetrate the physis posteriorly (arrow) to enter the epiphyseal cartilage. C: Close-up view showing the extent of the vascular supply of the trochlea. Note that no anastomoses are seen between these medial and lateral vessels. D: Lateral view through the medial crista of the trochlea. Note that the vessels penetrate the physis posteriorly (arrow) to enter the epiphyseal cartilage. (A–D: Reprinted from Haraldsson S. On osteochondritis deformans juvenilis capituli humeri including investigation of intraosseous vasculature in distal humerus. Acta Orthop Scand Suppl. 1959;38:1–232, with permission.) E: Radiograph of a 12-year-old boy. The persistence of the two separate ossification centers (arrows) of the media crista is seen. The area supplied by the lateral vessel.
A: Intraosseus vasculature in a 3-year-old boy. Only two small vessels supply the medial crista of the trochlea (arrows). The central portion of the crista appears avascular. B: In the lateral view through the medial crista of the trochlea, note that the vessels penetrate the physis posteriorly (arrow) to enter the epiphyseal cartilage. C: Close-up view showing the extent of the vascular supply of the trochlea. Note that no anastomoses are seen between these medial and lateral vessels. D: Lateral view through the medial crista of the trochlea. Note that the vessels penetrate the physis posteriorly (arrow) to enter the epiphyseal cartilage. (A–D: Reprinted from Haraldsson S. On osteochondritis deformans juvenilis capituli humeri including investigation of intraosseous vasculature in distal humerus. Acta Orthop Scand Suppl. 1959;38:1–232, with permission.) E: Radiograph of a 12-year-old boy. The persistence of the two separate ossification centers (arrows) of the media crista is seen. The area supplied by the lateral vessel.
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Figure 20-23
Blood supply of the trochlea.
A: Intraosseus vasculature in a 3-year-old boy. Only two small vessels supply the medial crista of the trochlea (arrows). The central portion of the crista appears avascular. B: In the lateral view through the medial crista of the trochlea, note that the vessels penetrate the physis posteriorly (arrow) to enter the epiphyseal cartilage. C: Close-up view showing the extent of the vascular supply of the trochlea. Note that no anastomoses are seen between these medial and lateral vessels. D: Lateral view through the medial crista of the trochlea. Note that the vessels penetrate the physis posteriorly (arrow) to enter the epiphyseal cartilage. (A–D: Reprinted from Haraldsson S. On osteochondritis deformans juvenilis capituli humeri including investigation of intraosseous vasculature in distal humerus. Acta Orthop Scand Suppl. 1959;38:1–232, with permission.) E: Radiograph of a 12-year-old boy. The persistence of the two separate ossification centers (arrows) of the media crista is seen. The area supplied by the lateral vessel.
A: Intraosseus vasculature in a 3-year-old boy. Only two small vessels supply the medial crista of the trochlea (arrows). The central portion of the crista appears avascular. B: In the lateral view through the medial crista of the trochlea, note that the vessels penetrate the physis posteriorly (arrow) to enter the epiphyseal cartilage. C: Close-up view showing the extent of the vascular supply of the trochlea. Note that no anastomoses are seen between these medial and lateral vessels. D: Lateral view through the medial crista of the trochlea. Note that the vessels penetrate the physis posteriorly (arrow) to enter the epiphyseal cartilage. (A–D: Reprinted from Haraldsson S. On osteochondritis deformans juvenilis capituli humeri including investigation of intraosseous vasculature in distal humerus. Acta Orthop Scand Suppl. 1959;38:1–232, with permission.) E: Radiograph of a 12-year-old boy. The persistence of the two separate ossification centers (arrows) of the media crista is seen. The area supplied by the lateral vessel.
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The lateral vessels supply the apex of the trochlea and the lateral aspect of the medial crista. These vessels cross the physis to enter the posterior aspect of the lateral trochlear ossification center. Their terminal branches lie just under the articular surface. Thus, they are particularly vulnerable to injury when the fracture line occurs through this area, as is typical in fractures of the medial condylar physis, lateral condyle, or a T-condylar fracture. By the same token, a fracture in the supracondylar area in which the fracture line is very distal or a total distal humeral physeal displacement can also disrupt the lateral trochlear epiphyseal vessels as they course along the surface of the metaphysis or at their entrance into the physeal plate. 
Another set of vessels enters medially through the nonarticulating surface of the trochlea. This set of vessels supplies the most medial aspect of the medial crista or the medial portion of the trochlear epiphysis. As shown in Haraldsson's studies,29,30 there appear to be no anastomoses between the two sets of vessels supplying the trochlear epiphysis. 
Ossification centers need blood supply for their appearance and development. Before these centers appear, the vessels are more superficial and less well defined. It is speculated that a lesion in these immature vessels in children leads only to a delay in the appearance of the centers. In older children, where there is already a well-defined ossification center, disruption produces a true bony osteonecrosis of one or both of the trochlea's ossification centers. This can result in a partial or total absence of further epiphyseal ossification, leading to either hypoplasia of the central or whole medial aspect of the trochlea respectively. 

Patterns of Osteonecrosis

Osteonecrosis of the trochlea can appear as either a central defect (type A) or total hypoplasia manifest by complete absence of the trochlea (type B), depending on the extent of the vascular injury. 

Type A—Fishtail Deformity

In the type A deformity, only the lateral portion of the medial crista or apex of the trochlea becomes involved in the necrotic process, which produces the typical fishtail deformity (Fig. 20-24). This more common pattern of necrosis seems to occur with very distal supracondylar fractures or with fractures involving the lateral condylar physis. 
Figure 20-24
Fishtail deformity.
 
A, B: Type A deformity. Osteonecrosis of only the lateral ossification center creates a defect in the apex of the trochlear groove. C: The typical fishtail deformity is seen in a radiograph of a 14-year-old boy who sustained an undisplaced distal supracondylar fracture 5 years previously.
A, B: Type A deformity. Osteonecrosis of only the lateral ossification center creates a defect in the apex of the trochlear groove. C: The typical fishtail deformity is seen in a radiograph of a 14-year-old boy who sustained an undisplaced distal supracondylar fracture 5 years previously.
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Figure 20-24
Fishtail deformity.
A, B: Type A deformity. Osteonecrosis of only the lateral ossification center creates a defect in the apex of the trochlear groove. C: The typical fishtail deformity is seen in a radiograph of a 14-year-old boy who sustained an undisplaced distal supracondylar fracture 5 years previously.
A, B: Type A deformity. Osteonecrosis of only the lateral ossification center creates a defect in the apex of the trochlear groove. C: The typical fishtail deformity is seen in a radiograph of a 14-year-old boy who sustained an undisplaced distal supracondylar fracture 5 years previously.
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Type B—Malignant Varus Deformity

The type B deformity involves osteonecrosis of the entire trochlea and sometimes part of the metaphysis (Fig. 20-25). This type of necrosis has occurred as a sequela of fractures involving the entire distal humeral physis or fractures of the medial condylar physis78 and can lead to a cubitus varus deformity in which the angulation progresses as the child matures. 
Figure 20-25
Osteonecrosis of the entire trochlea.
 
A: In this type B deformity, loss of blood supply from both the medial and lateral vessels results in osteonecrosis of the entire medial crista along with a portion of the metaphysis. B: Radiograph of a 4-year-old boy who sustained a type II physeal fracture involving the entire distal humeral physis. In this injury film, there is a large metaphyseal fragment on the medial side (arrow). C: As shown by the appearance 5 months later, a mild varus deformity is present because of an incomplete reduction. The ossification in the medial metaphyseal fragment has disappeared.
A: In this type B deformity, loss of blood supply from both the medial and lateral vessels results in osteonecrosis of the entire medial crista along with a portion of the metaphysis. B: Radiograph of a 4-year-old boy who sustained a type II physeal fracture involving the entire distal humeral physis. In this injury film, there is a large metaphyseal fragment on the medial side (arrow). C: As shown by the appearance 5 months later, a mild varus deformity is present because of an incomplete reduction. The ossification in the medial metaphyseal fragment has disappeared.
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A: In this type B deformity, loss of blood supply from both the medial and lateral vessels results in osteonecrosis of the entire medial crista along with a portion of the metaphysis. B: Radiograph of a 4-year-old boy who sustained a type II physeal fracture involving the entire distal humeral physis. In this injury film, there is a large metaphyseal fragment on the medial side (arrow). C: As shown by the appearance 5 months later, a mild varus deformity is present because of an incomplete reduction. The ossification in the medial metaphyseal fragment has disappeared.
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Figure 20-25
Osteonecrosis of the entire trochlea.
A: In this type B deformity, loss of blood supply from both the medial and lateral vessels results in osteonecrosis of the entire medial crista along with a portion of the metaphysis. B: Radiograph of a 4-year-old boy who sustained a type II physeal fracture involving the entire distal humeral physis. In this injury film, there is a large metaphyseal fragment on the medial side (arrow). C: As shown by the appearance 5 months later, a mild varus deformity is present because of an incomplete reduction. The ossification in the medial metaphyseal fragment has disappeared.
A: In this type B deformity, loss of blood supply from both the medial and lateral vessels results in osteonecrosis of the entire medial crista along with a portion of the metaphysis. B: Radiograph of a 4-year-old boy who sustained a type II physeal fracture involving the entire distal humeral physis. In this injury film, there is a large metaphyseal fragment on the medial side (arrow). C: As shown by the appearance 5 months later, a mild varus deformity is present because of an incomplete reduction. The ossification in the medial metaphyseal fragment has disappeared.
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A: In this type B deformity, loss of blood supply from both the medial and lateral vessels results in osteonecrosis of the entire medial crista along with a portion of the metaphysis. B: Radiograph of a 4-year-old boy who sustained a type II physeal fracture involving the entire distal humeral physis. In this injury film, there is a large metaphyseal fragment on the medial side (arrow). C: As shown by the appearance 5 months later, a mild varus deformity is present because of an incomplete reduction. The ossification in the medial metaphyseal fragment has disappeared.
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X

Clinical Presentation

Early there are often minimal, if any symptoms. When symptoms are present, they can include pain and loss of motion secondary to joint incongruity and locking, which is related to loose body formation and joint instability.10,40,54,57,58,76 
The clinical signs and symptoms differ considerably between the two patterns of necrosis. Patients who have the type A or fishtail deformity usually do not develop any angular deformities. The severity of the fishtail deformity is related to the degree of necrosis and seems to dictate the severity of the symptoms. In children who have a pattern of total osteonecrosis of the trochlea, including part of the nonarticular surface, a progressive varus deformity usually develops. Because the total medial trochlear surface is disrupted, significant loss of range of motion also develops. These deformities usually worsen aesthetically and functionally as the child matures. Early degenerative joint disease with a loss of range of motion is the most common sequela in severe cases. 
Some children with osteonecrosis of the trochlea develop late-onset ulnar neuropathy,52,67,74,80 thought to be due to a multiplicity of factors, including joint malalignment, abnormal position of the ulnar nerve and triceps tendon, loss of protection by a deep ulnar groove, and the acute angle of entrance of the two heads of the flexor carpi ulnaris. Rarely, a patient may present with fracture (Fig. 20-26). 
Figure 20-26
 
A: Twelve-year-old girl who had supracondylar humerus fracture treated with closed reduction and pinning at age of 5. B: She presented after a fall at age of 12 with a medial condyle fracture which was treated with open reduction and internal fixation (C).
A: Twelve-year-old girl who had supracondylar humerus fracture treated with closed reduction and pinning at age of 5. B: She presented after a fall at age of 12 with a medial condyle fracture which was treated with open reduction and internal fixation (C).
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A: Twelve-year-old girl who had supracondylar humerus fracture treated with closed reduction and pinning at age of 5. B: She presented after a fall at age of 12 with a medial condyle fracture which was treated with open reduction and internal fixation (C).
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Figure 20-26
A: Twelve-year-old girl who had supracondylar humerus fracture treated with closed reduction and pinning at age of 5. B: She presented after a fall at age of 12 with a medial condyle fracture which was treated with open reduction and internal fixation (C).
A: Twelve-year-old girl who had supracondylar humerus fracture treated with closed reduction and pinning at age of 5. B: She presented after a fall at age of 12 with a medial condyle fracture which was treated with open reduction and internal fixation (C).
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A: Twelve-year-old girl who had supracondylar humerus fracture treated with closed reduction and pinning at age of 5. B: She presented after a fall at age of 12 with a medial condyle fracture which was treated with open reduction and internal fixation (C).
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X

Radiographic Evaluation

Radiographically, in our series, loss of motion is associated with subluxation of the radial head.25 With proximal migration of the ulna, the coronoid impinges anteriorly and olecranon impinges posteriorly, leading to progressive loss of motion.33 Proximal migration of the ulna, radial head escape, or the combination of both may all lead to loss of motion. Plain radiographs can be used, but advanced imaging including the use of MRI or CT can better characterize the deformity and identify arthrosis and loose bodies.33,36,40 

Treatment

Descriptions of treatment options in the literature are extremely limited. In addition to observation and nonoperative care, proposed treatment options include debridement, capsulotomy,45,54 interposition arthroplasty, surgical arrest of the remaining medial or lateral physis,57 and osteotomy for persistent deformity.57 
Because the osteonecrosis of the trochlea is a direct consequence of trauma to the vessels at the time of injury, there is no effective prevention or treatment of the primary necrosis. Treatment is aimed at only the sequelae of the osteonecrosis of the trochlea. If a loss of range of motion is due to a significant disruption of the articular surface itself, there does not appear to be any good operative or nonoperative method that significantly improves elbow function. If the osteonecrosis of the trochlea has resulted in a varus deformity of the elbow, this deformity can be corrected by a supracondylar osteotomy with ulnar nerve transposition. The correction of the carrying angle may be aesthetic without functional improvement. Surgical treatment carries the risk of increased stiffness to the already limited elbow. 
In our experience, small defects with minimal joint involvement can be observed.25 In patients with extensive joint involvement, associated with loss of motion, elbow stiffness, or loose bodies, arthroscopic debridement may help transiently improve symptoms including pain and limited range of motion. As one would expect, symptoms commonly recur and long-term outcomes are unknown. Therefore in patients who have limited deformity and mild symptoms, arthroscopic debridement can prove to be useful, particularly if there is limited medial and lateral growth of the distal humerus remaining. It may be the only salvage option for symptomatic patients with significant deformity and subluxation of the radial head. 
If there is growth remaining in the medial or lateral physis, physeal closure may be of benefit in some patients. Nwakama et al.57 has suggested that surgical closure of the lateral and/or medial portions of the physis to prevent the progressive intracondylar notching leads to proximal ulnar migration. Unfortunately there are no studies that have outlined long-term follow-up from epiphysiodesis. However, we believe that this technique is beneficial in patients with open physes, a mild deformity, and a congruent radiocapitellar joint. 

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