Residual bone cysts after Ilizarov treatment of relapsed clubfeet.

The Ilizarov technique is well established as an effective method of treating clubfoot deformities. A complication of this method is the development of cysts in the bones of the foot. The purpose of this study was to clarify the incidence, presentation, and etiology of these cysts. The radiographs of 17 feet that had undergone Ilizarov treatment for a clubfoot deformity were reviewed. In nine of the feet, discrete, well demarcated lucencies of bone were detected. They occurred in both tarsal and metatarsal bones, but most commonly in the base of the fifth metatarsal. Magnetic resonance imaging examination of two feet demonstrated a normal marrow signal. suggesting that the cysts are due to localized trabecular resorption with the space being filled with marrow fat.