THE NATURAL-HISTORY OF HIP DEFORMITY IN MYELOMENINGOCELE

We studied 1061 children with myelomeningocele, reviewing 3184 pelvic radiographs from 802 patients. Hip dislocation had occurred by the age of 11 years in 28% of children with a thoracic neurosegmental level, 30% of those with an L1/2 level, 36% of L3, 22% of L4, 7% of L5 and on ly 1% of those with sacral levels. Hip dislocation was not inevitable even when there was maximal muscle imbalance about the hip. The averag e hip flexion contracture in children aged 9 to 11 years was significa ntly greater in those with thoracic (22-degrees) and L1/2 (33-degrees) levels than in those with L4 (9-degrees), L5 (5-degrees) or sacral (4 -degrees) levels. Our findings indicate that muscle imbalance is not a significant factor in the production of flexion deformity or dislocat ion of the hip; both are commonly seen in the absence of imbalance. Th e restoration of muscle balance should no longer be considered to be t he principal aim of the management of the hip in children with myelome ningocele.