Valgus deformity of the ankle in children with spina bifida aperta.

Valgus deformity of the hindfoot can occur at the subtalar joint, the ankle joint, or at both sites. In children suffering from spina bifida, the ankle is often the main site of deformity. Thirty-five ankles with valgus deformity of the hindfoot were studied in 23 children with spina bifida. A radiological triad was observed in all patients: shortening of the fibula, lateral wedging of the distal tibial epiphysis, and lateral tilt of the talus at the ankle mortise . There was a definite correlation between the severity of wedging and the degree of talar tilt, and a fair correlation between the severity of wedging and the extent of fibular shortening. The results of operation in 12 feet are presented. It is concluded that any operations performed below the ankle on these patients (subtalar fusion or triple arthrodesis) is unlikely to succeed; the deformity needs to be corrected above the ankle (by epiphysiodesis or supramalleolar osteotomy). Radiological assessment of the ankle by taking weight-bearing films in the anteroposterior plane is essential to determine the true extent of the deformity before undertaking any operation.