The pathogenesis and surgical management of foot deformity in Charcot-Marie-Tooth disease

The foot deformities in CMT follow certain general patterns; however, like the underlying motor failures that cause them, the deformities present in each patient are unique, and care must be individualized. There is no simple algorithm that can be applied to all patients. The hindfoot, forefoot, and toe deformities in CMT all ultimately are interconnected. As a general rule, it makes sense to address the plantar fascia, then proceed from the hindfoot to the forefoot in analyzing the deformities and in surgery. Releasing the plantar fascia may alter the amount of bony correction required in any concomitant hindfoot procedure. Likewise, only after the heel is realigned can any residual forefoot valgus be assessed, and a hindfoot procedure may alter the resting tension of the digital flexors and extensors. Finally, if a patient has purely dynamic clawtoes preoperatively, the toes may appear perfectly normal in the operating room with the ankle plantar flexed. Tightness of the flexor digitorum longus should be elicited by bringing the ankle up to neutral as a final check. The variety of foot deformities in CMT present a unique challenge to the orthopedic foot and ankle surgeon. It is vital for the patient and physician to remember that CMT is an inexorably progressive disease, and an initially good result can deteriorate with changing motor function. With meticulous attention to the neurologic examination and the balance of supple and fixed deformities in the foot, very satisfying outcomes usually can be obtained.