Hip Dislocation and Subluxation in Cerebral Palsy

Four hundred sixty-four patients with cerebral palsy were reviewed. They were placed in four function groups: independent ambulators (n = 76), dependent ambulators (n = 43), independent sitters (n = 41), and dependent sitters (n = 304). The percentage of subluxated or dislocated hips increased from 7% for independent ambulators to 60% for dependent sitters. In the dependent sitters, a level pelvis or different degrees of pelvic obliquity did not correlate with whether the hip was located, subluxated, or dislocated. The subluxated or dislocated hip did not correlate with the high side or the amount of pelvic obliquity. Muscle imbalance around the hip and not the pelvic obliquity is the cause of the hip subluxation or dislocation.