Current Concepts With External Fixation And The Charcot Foot
Combining a thorough review of the literature with insights from their surgical experience, these authors assess the role of external fixation and offer recommendations in procedure selection for addressing deformities in patients with Charcot neuroarthropathy.
The original application of external fixation in Charcot neuroarthropathy included static fixation following corrective osteotomies and/or arthrodesis. In 1996, Sticha and colleagues reported on the use of Kirschner wire fixation and three unilateral mini-external fixators for midfoot arthrodesis in patients with chronic Charcot neuroarthropathy deformity.1 Wang and coworkers utilized hybrid external fixation in 2002 for successful arthrodesis of 28 non-ulcerated patients with Charcot neuroarthropathy in combination with tendo-Achilles lengthening and bone stimulation.2 Farber and colleagues demonstrated good results with ulcer excision and open osteotomy with static external fixation.3 In 2002, Cooper found more varied results in a group of 100 patients using acute open reduction with mostly static external fixation.4
In 2006, Pinzur used circular external fixation to maintain alignment of deformity correction in high-risk, obese patients with Charcot neuroarthropathy.5 The ability to use external fixation safely in cases of large bone loss due to infection established an advantage in treating severe Charcot neuroarthropathy foot and/or ankle osteomyelitis. Pinzur reported a single-staged technique in 26 high-risk patients with midfoot Charcot neuroarthropathy and osteomyelitis via resection of the infected bone, deformity correction with circular external fixation, and culture-specific parenteral antibiotic therapy.6 In 2007, Lamm and Paley advocated gradual deformity correction using Ilizarov external fixation for severe Charcot neuroarthropathy dislocations and deformities.7 They cited the benefits of a minimally invasive technique without sacrificing foot length, limiting neurovascular compromise and allowing partial weightbearing.
Since then, other authors have reported on their results using single- or multiple-staged limb salvage for diabetic Charcot neuroarthropathy osteomyelitis of the foot and/or ankle.8,9 The versatility of external fixation with appropriate technique has also allowed surgeons to combine this with internal fixation such as intramedullary nails or locking plate technology for Charcot neuroarthropathy.10,11 Although there is controversy in this area, surgeons have applied external fixation in the acute stage of Charcot neuroarthropathy and/or in acute neuropathic fractures to prevent joint collapse and subsequent deformity.12 In recent years, with the increased use of soft tissue reconstruction in patients with Charcot neuroarthropathy, creatively designed external fixators have also become an additional tool to properly offload grafts or flaps in patients who are unable to tolerate conventional techniques such as cast immobilization.13
Identifying The Challenges With Diagnosis
The clinical presentation of Charcot neuroarthropathy is varied and its pathophysiology is still unknown. Some of the most common theories have suggested that autonomic and/or sensory neuropathy may predispose the patient with diabetes to the initial cascade of the Charcot neuroarthropathy process. Other suggestions have concentrated on pro-inflammatory cytokines, glycosylated tendon(s), biomechanical lower extremity alterations, digital or partial foot amputations, severe infection/cellulitis, osteomyelitis, decreased bone mineral density and vitamin D levels.14-17