THIRTY-YEAR FOLLOW-UP STUDY OF ROTATIONAL ACETABULAR OSTEOTOMY

Abstract

Satisfactory intermediate and long-term results of rotational acetabular osteotomy (RAO) for the treatment of early osteoarthritis secondary to developmental dysplasia of the hip have been reported. The purpose of this study is to examine the 30-year results of RAO.Between 1987 and 1994, we treated 49 patients (55 hips) with RAO for diagnosis of pre- OA or early-stage OA. Of those patients, 35 patients (43 hips) were available at a minimum of 28 years. The follow-up rate was 78.2% and the mean follow-up was 30.5 years. The mean age at the time of surgery was 34 years. Clinical evaluation was performed with the Merle d'Aubigne and Postel rating scale, and radiographic analyses included measurements of the center-edge angle, acetabular roof angle, and head lateralization index on preoperative, postoperative AP radiographs of the pelvis. Postoperative joint congruency was classified into four grades. The radiographic evidence of progression of OA was defined as the minimum joint space less than 2.5mm.The mean preoperative clinical score was 14.0, which improved to a mean of 15.3 at the time of the latest follow-up. The mean center-edge angle improved from 0.6° preoperatively to 34° postoperatively, the mean acetabular roof angle improved from 28.4°preoperatively to 1.0°postoperatively, the mean head lateralization index improved from 0.642 preoperatively to 0.59 postoperatively. Postoperative joint congruency was excellent in 11 hips, good in 29 hips, and fair in 3 hips. Nineteen patients (20 hips) had radiographic OA progression, and 10 patients (11 hips) were converted to THA. Kaplan-Meier survivorship analysis, with radiographic OA progression as the end point, predicted survival of 75.6% at 20 years and 48.8% at 30 years, and with THA conversion as the end point, 90.2% at 20 years and 71.2% at 30 years.The RAO is an effective surgical procedure for symptomatic dysplastic hips of pre- and early-stage OA and could change the natural history of the dysplastic hip.