Effect of surgery on the nontreated hip in severe cerebral palsy.

We studied the fate of the nonoperated hip in 35 patients with cerebral palsy who underwent surgical stabilization for unilateral hip subluxation (24 patients) or dislocation (11 patients). Review of medical records and radiographs was performed and analysis was accomplished on the effect of preoperative and radiographic variables on the radiographic outcome of the nonoperated hip. The average age at surgery was 5.5 years and at follow-up was 9.7 years, with an average follow-up of 4.2 years. Before subsequent surgery (in 15 nonoperated hips) or at follow-up, 10 of the nonoperated hips were dislocated and 16 hips were subluxated. Hips were stable and less likely to have surgery if they had a lower initial migration index and higher center edge angles. We conclude that there are few indications for unilateral hip surgery in patients with diplegia or quadriplegia undergoing initial hip stabilization surgery, especially if any degree of dysplasia is present.