Evaluation of isokinetic hip strength after rotational acetabular osteotomy.

Fifty-four patients with dysplastic hip and secondary degenerative arthrosis (58 hips) underwent rotational acetabular osteotomy (RAO) using a conventional anterior-posterior method or a new technique involving detachment of the greater trochanter. Pre- and postoperative hip abductor strength (HAS) and knee extensor strength (KES) were evaluated using an isokinetic dynamometer. Postoperative HAS in patients treated by detachment of the greater trochanter reached preoperative levels 16 weeks postoperatively. Comparison of the postoperative HAS based on the two different surgical approaches showed that RAO by detachment of the greater trochanter was superior to the conventional method. Pre- and postoperative HAS showed a good correlation. Postoperative improvements in HAS over presurgical values were not significant in patients with advanced-stage arthrosis and severely dysplastic hips. Preoperative HAS should serve as an index for determining whether RAO is undertaken using detachment of the greater trochanter.