Infection after Fracture
Acute Posttraumatic Osteomyelitis
Clinical and Laboratory Diagnostic Tests
Other Scintigraphic Methods
Magnetic Resonance Imaging
Cultures and Biopsy
Management and Treatment
Antibiotic Depot Devices and Techniques
Considerations in the Geriatric Patient
Author’s Preferred Methods
Data from www.sigmaaldrich.com/Area_of_Interest/Biochemicals/Antibiotic_Explorer/Mechanism_of_Action.html.
Fluoroquinolones: ciprofloxacin 750 mg PO BID, levofloxacin 500 mg PO QD, moxifloxacin 400 mg PO QD.
Note that use of fluoroquinolones has been associated with altered bone healing in animal models and increased risk of tendon rupture in humans.
Note that many antibiotics may result in development of severe colitis.
The authors assume that any patient with a history of surgical fracture treatment, subsequent drainage, wound dehiscence, antibiotic treatment, or unplanned surgery may potentially have osteomyelitis. Many of these patients present with a paucity of medical records and other details, and often their own recollection of events is poor. Therefore, we presume infection until we have strong evidence to the contrary, particularly if symptoms occur in conjunction with fracture nonunion.
The host is classified first and efforts are made to optimize the host status. Improving nutrition and tissue oxygenation is important before embarking on surgical treatment. Occasionally, hyperbaric oxygen is helpful if it is available and can be tolerated by the patient. Ideally, the patient should stop smoking, but this is generally difficult to accomplish. However, we encourage patients to limit nicotine use because it is thought that nicotine causes local microvascular effects. Therefore, nicotine patches and gum, although useful for smoking cessation programs, may not be useful for local tissue optimization. We now routinely check vitamin D levels in all cases of delayed or failed osseous healing. Supplementation is usually 50,000 units per week for several weeks but underlying causes of the deficiency should be sought and corrected. Consultation with a primary care physician will help stabilize chronic medical conditions in many patients.
The limb is also evaluated for its ability to tolerate surgical intervention. Multiply operated limbs are B local by definition and heavily scarred and immobilized tissues may present risks for subsequent wound healing. Some patients may not be candidates or may not tolerate the extensive surgery that is required, and therefore compromises in treatment and patient expectations may be necessary. Many surgeons are now opting to treat exposed bone with a vacuum-assisted closure (VAC) device. Although this can often produce a healthy granulating tissue bed, it should be remembered that the underlying bone is compromised and has a higher risk of nonunion and infection. Another problem is that the soft tissue envelope tends to be an adherent layer of scar over the bone, which may not tolerate secondary surgery well. Secondary surgery under these circumstances may well result in further infection. For this reason, we still advocate the use of healthy muscle or fascial flaps that not only help being an external blood supply to the surface of the bone but can better tolerate subsequent surgical procedures.
Initially, laboratory testing including assessment of the WBC, ESR, and CRP is undertaken. If these tests are negative and there is no further reason to suspect infection, then we treat the patient as having an aseptic nonunion but we will pay attention to our intraoperative findings. If there is any indication of infection despite normal laboratory findings, we obtain intraoperative cultures or undertake a biopsy and await results. One common scenario is a presumed aseptic case where routine cultures end up growing a few colonies of bacteria. The issue is whether the culture results represent a real infection or contamination. In these cases, we discuss the surgical findings with the infectious disease specialist who explains their assessment of the validity of the cultures. If we believe that the risk of infection is low, we may cover the patient with a short course of culture-specific oral antibiotics. However, if we believe that the risk is high, we use a longer course of antibiotic treatment. We have found that even when there is little diagnostic and operative evidence of infection, patients may still develop later infection. We have no way of knowing if the subsequent infection was a resurgence of an old occult infection or a secondary infection from the recent surgical intervention. A recent study found that over 20% of nonunion cases, that had cultures taken intraoperatively, had positive cultures. These patients were given antibiotics and just over 2% developed infection from the same organism as was cultures preoperatively.120
In cases in which we suspect infection but do not know the organism, we will often remove the initial hardware and then take numerous cultures and biopsy samples of bone and soft tissue (often six or more). We will then temporarily stabilize the bone in the least invasive manner using a cast, brace, or monolateral external fixator. Sometimes it is helpful to obtain two different sets of cultures. One set of cultures is obtained from the most suspicious areas during the initial part of the surgical procedure. The second set of cultures is obtained after debridement from the margins of the tissue bed. If this methodology is used, one can assess whether the debridement was adequate, especially if the initial cultures were positive. If we remain uncertain about the extent of the infection, we will attempt to use MRI with contrast to determine the intramedullary and soft tissue extent of the infection and then plan our treatment accordingly. Unfortunately, in a majority of cases, there is implanted metal, which makes the use of MRI less applicable. When possible, we use scintigraphic studies preoperatively despite their limitations. We have anecdotally noted significant variations in the accuracy of the readings between various radiologists and encourage working with a few radiologists who are interested and experienced with musculoskeletal infection. Because of our own findings and those in the literature, we now depend less on scintigraphy than on other signs and generally no longer use the red cell scan. The initial findings of PET scanning are encouraging.
Once infection has been confirmed, an organism is identified, and the extent of the infection is delineated, we decide whether the goal is to cure the infection, suppress the infection, or recommend amputation. In compromised hosts, cure can usually be achieved only by complete excision of all the infected tissue, which often means that amputation is required. In healthier hosts, marginal resection leaving some bacteria behind or even intralesional resections when the infection is periarticular can lead to cure with appropriate antibiotic therapy. Generally speaking, our preference is to advise the patient that resection with a clean margin has the best chance of cure.
If bone resection and limb salvage are chosen, we follow the general principles that bone defects of 6 cm or greater require bone transport with distraction osteogenesis, whereas smaller defects can often undergo bone grafting. In the tibia, we prefer the posterolateral tibia-pro-fibula technique, but in some cases we will undertake central bone grafting. We try to avoid the exclusive use of demineralized bone matrix (DBM) and allograft because we have found a relatively low incidence of bone union. The low success rates using DBM products may be because of the poor vascularity found in such tissue beds and patients. Anecdotally, we have noted cases where patients present years after failed DBM grafting of the distal tibia, and during reoperation the original DBM material appears to be unchanged. This indicates failure of angiogenesis (Fig. 26-20). DBM reports in the literature are limited but they do not support its general use as a bone graft substitute for nonunions, especially if there is bone loss. Ironically, cases in which bone graft is most needed, such as those where there is poor bone vascularity or a compromised host, are those in which DBM is of least value and the success of DBM may well be in those cases where bone graft is not needed.132
Bone morphogenetic proteins (BMPs) show significant promise and they are a much more powerful inductive agent than DBM. Currently surgeons still have to use them “off-label” as they have not been released for general use. There are numerous anecdotal cases of their successful use in nonunion and infection surgery, and their usefulness in limb salvage is unquestionable. However, there are some concerns about their potency and their use in females considering pregnancy within a year of its use.
The newer technique of graft harvest with the RIA has been shown to be successful for large defects and the graft harvested seems to have excellent osteogenic potential. Mixture with BMP may provide an even greater effect because the BMP is acellular and only an inductor, whereas the RIA aspirate supplies conductive elements and cellular components needed for healing. Experience with RIA has been positive.72,97
Another technique combining the use of RIA graft with an induced biomembrane has gained some popularity. The technique of Masquelet incorporates a cement spacer into the defect after bone resection. A biologic membrane grows over the spacer and the spacer is removed weeks to months later, once antibiotic elution has concluded. At the time of spacer removal, the membrane is maintained as best as possible to promote angiogenesis and a large-volume autograft, using iliac crest or RIA, is placed within the site.
If there is a sinus tract, we have found the technique of injecting diluted methylene blue dye into the sinus tract very helpful in localizing the path to any deep collection of fluid or sequestrum (Fig. 26-21). It helps minimize the amount of local tissue resection. The technique is relatively simple but does not always identify the whole lesion. Sinus tract resection is undertaken using a longitudinal elliptical skin incision to allow closure. The deep dissection follows the tract until the bone component is identified. Bone debridement is undertaken based on involvement. If the bone involvement is such that it is a Cierny III where there is axial stability, then all efforts are made to maintain axial stability, and avoid turning a type III lesion into a type IV, although sometimes this is not possible. Type IV lesions by definition require supplemental fixation and reconstruction. Some extensive type III lesions, although having some axial connection, are still unstable and may require additional treatment, thus essentially making them a type IV lesion. In salvageable type III lesions, we do not undertake a bulk resection and we often use a high-speed water-cooled burr to remove only as much bone as necessary.
In obvious type IV lesions, bone reconstruction is mandatory and it is a matter of how much reconstruction is required. We have found that bone transport is the most reliable method for reconstruction. This is discussed in Chapter 28. In certain areas, or in patients where transport may not be tolerated, the Masquelet technique or the use of bone cages with massive graft and BMP are the only other alternatives.
The use of antibiotic-coated nails for infected nonunions continues to evolve. Several reports have shown the efficacy of statically locked nails that are coated with a 2-mm cement mantle. We increasingly use this technique for infected long bone nonunions. The antibiotic cement must be mixed early in the procedure and the nail should be coated by the use of oversized cardiac pump tubing or other large bore tubing that is sterile and can be easily removed. We have not found chest tubes to be large enough. A 9-mm nail is selected for the tibia or femur. The nail and cement are prepared at the start of the case and the cement is allowed to cure on the nail for at least 45 minutes. The use of tubing insures a smooth, glass-like coating, which combined with the curing process, decreases the likelihood of debonding at insertion. The canal is overreamed by at least 5 mm to accommodate the nail and the cement. Once inserted, distal and proximal interlocking is undertaken using standard techniques. The nail permits early weight bearing. In cases of bone loss, we perform later grafting at 8 to 12 weeks, once the ESR and CRP tests are normal and the antibiotics have been stopped.45,100,103
In general, the mainstay of reconstruction for complex infection remains the bone transport techniques described by Ilizarov. These are described in detail in Chapter 28. Although this technique is not simple for either the patient or the surgeon, there are notable advantages compared with grafting techniques. These include the early development of regenerate bone soon after bone resection. If bone grafting is used, one must wait 8 weeks or longer as part of a staged reconstruction plan. Also, the effects of corticotomy include increasing blood flow in the limb for 4 to 6 weeks, and this may have a positive effect in infection cases. Most importantly, function is improved. The patient is encouraged to weight bear and to resume most activities of daily living. In many cases, patients can return to work, participate in recreational activities, and even swim. In cases where transport takes a considerable period or where transport has finished but one has to wait for maturation of regenerate bone, we have used long percutaneously inserted locked plates as an internal fixator that spans and protects maturing regenerate bone. This allows for early removal of the ring fixator (Fig. 26-22). Alternatively, some cases are amenable to transport over a nail (Fig. 26-23). We encourage surgeons who wish to treat bone infection to be familiar with Ilizarov method and to seek out appropriate training.
A key component in the management of infection is functional rehabilitation. Often, the patients are extremely debilitated from years of disability because of their condition. Treatments that permit early weight bearing and encourage range of motion in adjacent joints promote physical and psychological well-being. It is unusual for treatment to fail because patients have been walking on their limb. Usually failure is caused by inadequate resection, inadequate stability, and inadequate biology.
It is very difficult for surgeons who operate infrequently on infection to achieve the results published by experts. Not only is bone transport labor intensive but successful treatment requires an integrated team who are trained and willing to meet the demands of the patients and to facilitate the work of the surgeon. It is also imperative to collaborate and enlist the expertise of colleagues in infectious disease, psychiatry, medicine, microvascular surgery, social work, physical therapy, and occupational therapy. All staff must also be aware of the special needs of these patients, many of whom have undergone multiple failed procedures. It is very common to find depression, anxiety, and other psychological issues in both patients and their families. In fact, the burdens of the caregiver have only recently been identified, with many caregivers reporting depression, financial loss, and other problems as they care for their family members.130
There is no doubt that, given the difficulties of treating bone infection, the best strategy is prevention. Surgeons have always been aware of this, but recently the medical community, patients, and bodies that fund medicine have become more aware of the problem. As a consequence of this, increased research is expanding our knowledge of surgical infection and this has significant implications for the prevention of osteomyelitis. There is more knowledge about the factors that increase the risk of infection. Controllable patient factors such as perioperative body temperature, glucose levels, and preoperative hygiene are being standardized. Improved surgical techniques and the optimization of the patient environment are also having an effect, and hopefully we will be able to minimize the incidence of osteomyelitis in the future.
Tribute to George C Cierny III Orthopedic surgeons, particularly those who treat osteomyelitis, were saddened by the loss of George C. Cierny III last year on June 24th, 2013. Dr. Cierny was pivotal in studying and understanding the treatment of bone infections. His incredible energy and drive resulted in the accumulation of data that transformed the diagnosis, classification, and treatment of osteomyelitis. With his partner Dr. J. Mader (infectious disease), they developed the widely quoted and utilized Cierny-Mader classification of osteomyelitis. Dr. Cierny and Mader recognized the importance of the host, and approached osteomyelitis in a systematic way, intuitively recognizing the utility of applying the principles of tumor surgery to bone infections. His surgical skills and patient care were difficult to match, and he was internationally sought as a surgeon and speaker. Dr. Cierny was a physician who worked for weeks on a specific plan for each patient, revisiting the plan daily and making changes until he felt it was perfect. Perfection is what he demanded of himself and everyone around him, including the patient. This was particularly true in the operating room. He was a founding member of the Musculoskeletal Infection Society (MSIS), and has left behind a legacy for his colleagues, students, and friends. Orthopaedic surgeons are indebted to him and will miss his veracity and wisdom.
Tribute to George C Cierny III
Orthopedic surgeons, particularly those who treat osteomyelitis, were saddened by the loss of George C. Cierny III last year on June 24th, 2013. Dr. Cierny was pivotal in studying and understanding the treatment of bone infections. His incredible energy and drive resulted in the accumulation of data that transformed the diagnosis, classification, and treatment of osteomyelitis. With his partner Dr. J. Mader (infectious disease), they developed the widely quoted and utilized Cierny-Mader classification of osteomyelitis. Dr. Cierny and Mader recognized the importance of the host, and approached osteomyelitis in a systematic way, intuitively recognizing the utility of applying the principles of tumor surgery to bone infections. His surgical skills and patient care were difficult to match, and he was internationally sought as a surgeon and speaker. Dr. Cierny was a physician who worked for weeks on a specific plan for each patient, revisiting the plan daily and making changes until he felt it was perfect. Perfection is what he demanded of himself and everyone around him, including the patient. This was particularly true in the operating room. He was a founding member of the Musculoskeletal Infection Society (MSIS), and has left behind a legacy for his colleagues, students, and friends. Orthopaedic surgeons are indebted to him and will miss his veracity and wisdom.