Incidence and type of hindfoot deformities in patients with low-level spina bifida.

In a consecutive series of 174 children with low-level spina bifida, there was hindfoot deformity in 263 of the 348 feet; 86 were in equinus, 108 were in calcaneus, 41 were in valgus, 20 were in varus, and eight had convex pes valgus. Surgery was performed on 222 (64%) feet. The deformities were symmetric in 114 children. Spasticity causing deformity necessitated surgery in only 44 feet. Calcaneus deformity in the foot is considerably more common in patients with L4 lesions, and in these circumstances, muscle imbalance is clearly a major factor. However, many patients with calcaneus deformity had L5 or sacral lesions. This suggests that muscle imbalance is not so important a factor as has been thought in the causation of deformity in the lower limb in myelomeningocele.