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

By George Liu, DPM, FACFAS

Historically, surgeons have utilized circular and monolateral external fixation for the management of complicated high-energy orthopedic trauma and reconstruction of congenital or posttraumatic deformities through the Ilizarov and deBastiani principles of callotasis and distraction osteogenesis.1-3 Demonstrating success in bone healing and deformity correction in limbs that would have otherwise left patients with permanent disabilities or necessitated limb amputation, external fixation has found its way into the treatment of Charcot foot, arguably one of the most challenging problems for patients with diabetes. As our understanding of the Charcot disease process has evolved in regard to the disease’s pathophysiology, the optimal intervention period and identifying limitations with traditional internal fixation methods, external fixation seems to be the next step in Charcot treatment. However, as with anything new that takes center stage, there will always be undefined uses that invite controversy and debate. While the incidence rate for Charcot neuroarthropathy is low (occurring in less than 0.3 to 0.9 percent of patients with diabetes per year), Charcot neuroarthropathy is considered one of the more devastating manifestations of profound neuropathy and longstanding diabetes mellitus.4,5 While the condition is commonly associated with joint destruction, subluxation/dislocation and instability, four- and 10-year retrospective longitudinal studies from diabetes specialty clinics evaluating the natural history of this neuropathic arthropathy revealed that Charcot rarely led to limb loss when patients were diagnosed and managed early in the disease process.4,6 Additionally, researchers found that surgical intervention was only necessary in 25 percent of all patients surgeons followed for acute Charcot neuroarthropathy. Out of this group, surgeons treated 64 percent of patients successfully with exostectomies and only 36 percent necessitated arthrodesis. In their 10-year retrospective series of 115 patients with Charcot, Fabrin et al., reported that 5 percent required surgical intervention with 2 percent undergoing below-knee amputation and 3 percent requiring arthrodesis.4 Achieving stable internal fixation may be difficult in the Charcot foot with localized osteoporotic bone, large spatial defects from either joint destruction or resection of osteomyelitis. Usually, these cases of significant bone loss require bone grafting for structural support and long screws and large plates to span the defect. In cases of longstanding deformities, single-stage corrections may be limited by chronic soft tissue contractures and peripheral scarring of the neurovacsular bundle, leading to complications of inadequate deformity correction, wound dehiscence and local ischemic tissue loss. Complications with wound healing, poor screw purchase, hardware failure, nonunion and recurrence of deformity are potential sequelae of open arthrodesis with internal fixation in Charcot reconstruction. External circular fixation can provide mechanical stability to structurally deficient bone and maintain skeletal alignment where internal fixation options for direct stabilization are limited. A Closer Look At The Ex-Fix Controversy There has been evidence to suggest that external fixation methods can provide advantages in Charcot reconstruction when internal fixation is unsuccessful. However, much of the controversy surrounding external fixation stems from the lack of consensus regarding treatment goals and indications for use. The utilization of circular fixation for Charcot is broad and has been reported for: • the management of skeletal defects associated with surgical resection of osteomyelitis; • acute fracture dislocations; • gradual deformity correction; • static neutralization frames to protect high risk fusion sites in patients not capable of non-weightbearing; • elective rearfoot/ankle fusions; • protecting fasciocutaneous flaps; and • offloading ulcers. As logical as this may seem to some surgeons, this widespread use has not been accompanied with meaningful statistical evidence to justify the role of ex-fix in Charcot foot reconstruction yet there is continued nationwide promotion of its use.

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