Established hip dislocations in children with cerebral palsy.

Hip dislocation in children with cerebral palsy is caused by a combination of factors, including spastic muscle imbalance, persistent fetal femoral geometry, acetabular dysplasia, and flexion-adduction contracture. The incidence of dislocation correlates with the severity of the spasticity, and the prevalence is close to 50% in neurologically immature, spastic quadriplegic children. Successful hip reductions improve muscular balance, provide satisfactory reduction of the femoral head, and establish good pelvic coverage. In 31 occurrences of established hip dislocation in 24 patients, the most successful operations used a combined procedure consisting of soft-tissue release, open reduction, femoral varus derotation and shortening osteotomy, and pelvic osteotomy.