Is External Fixation Overutilized In Managing Charcot In The Diabetic Foot?

Author(s): 
By George Liu, DPM, FACFAS
Additionally, few studies examine the same outcomes for success. The lack of uniform outcome measures makes it difficult to interpret the existing literature and generate meaningful comparisons as to whether surgical reconstruction is superior to total contact casting, and whether external fixation is superior to internal fixation. External fixation comes with a considerable economic price and patient risk. The cost of external fixation may range from $6,000 to $30,000 per patient for initial application. Additionally, experts have quoted a 100 percent complication rate with external fixation in Charcot reconstruction. Therefore, with a device which requires frequent postoperative follow-up, has high complication rates and is cost prohibitive, the indications of external fixation need to be clear. For external fixation in Charcot reconstruction, the risk to benefit ratio for unconventional applications may be disproportionately high in comparison to that of internal fixation. By using this device on the diabetic foot, you must ask: Are you saving the limb or putting it at risk? Should You Consider External Fixation Over Internal Fixation? In general, most of the literature agrees that one should consider surgical reconstruction when Charcot deformity is: acutely or chronically unstable, nonplantigrade, unshoeable/unbraceable or when it is associated with longstanding ulceration unresponsive to traditional offloading methods. The question is not who is a candidate for external fixation but who is not a candidate for internal fixation. Osteopenic bone. Bone demineralization in the Charcot foot may be the result of disuse of the limb from nonweightbearing or offloading treatments, or may be due to local pathology one may see in the acute Charcot process.7,8 Researchers have considered decreased bone mineral density as a risk factor for complications such as hardware failure and loss of deformity correction due to insufficient stability or purchase of internal fixation.9,10Osteomyelitis and large skeletal defects. In the presence of infected bone, the introduction of internal fixation may serve as a source for infection involving unaffected areas of adjacent bone. With staged procedures involving wound debridement, one must often excise infected bone and provide long-term parental antibiotic therapy prior to introducing internal fixation for final reconstruction. In addition, structural defects may require a large bone graft with long reconstruction or locking plates and screws to achieve direct stabilization. This method often requires wide surgical exposure, stripping the periosseous blood supply to the bone and increasing the probability for nonunion. External fixation may provide indirect stabilization of the skeletal defect spanning the area of bone resection or to protect bone graft through percutaneous methods that limit soft tissues exposure. Inability to offload the affected limb. Overweight and obese patients are significantly associated with diabetes, cardiovascular disease, arthritis and general poor health status.11 The energy consumption required for five minutes of three-point crutch ambulation is markedly elevated as it reportedly increases the heart rate by 53 percent and oxygen uptake by 32 percent.12 Combined with limited cardiac reserve and obesity, most Charcot patients demonstrate difficulty or an inability to offload the affected limb safely despite physical therapy training. With unintentional weightbearing, the patients’ excessive weight may exceed the mechanical limits of internal fixation devices, compromising the purchase of these devices to bone or causing implant failure. External fixation may provide stable reduction of the realignment arthrodesis, simultaneously allowing a shared loading of the fusion site without exceeding the mechanical limits of the fixator maintaining the correction. Unstable or non-braceable limb deformities. Both acute and chronic Charcot neuroarthropathy may result in severe and unstable limb deformities that are not structurally stable for weightbearing.

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