The Wagner spherical osteotomy of the acetabulum. Surgical technique

The purpose of this study was to evaluate the long-term clinical and radiographic results of spherical acetabular osteotomy, performed with the surgical technique described by Wagner, in patients with hip dysplasia.

The results of the first twenty-two spherical osteotomies performed by one surgeon at one institution were reviewed at a minimum of twenty years (median, 23.9 years; maximum, 29.3 years) postoperatively. Preoperative and follow-up radiographic measurements included the lateral and anterior center-edge angles, acetabular index angle, and acetabulum-head index of Heyman and Herndon. Anteroposterior radiographs of the pelvis were evaluated for the presence of joint congruency, joint-space narrowing, increased sclerosis of the subchondral bone, and bone cysts. Clinical evaluation was performed with use of the Harris hip score.

Osteotomy improved the mean lateral center-edge angle from -2 degrees to +13 degrees and the mean acetabulum-head index from 52% to 72%. The mean postoperative anterior center-edge angle was 23 degrees (range, -1 degrees to 62 degrees ). Seven (32%) of the twenty-two hips were converted to a total hip replacement. At the latest follow-up examination, the average Harris hip score of the remaining fifteen patients was 86 points (range, 50 to 100 points). The clinical result was rated good or excellent for eleven of the fifteen patients. At the latest follow-up examination, the severity grade of the osteoarthritis was unchanged in thirteen hips. Only three of the nine hips that subsequently required a total hip replacement or that showed progressive osteoarthritis had been congruent after the index operation, whereas ten of the thirteen hips that did not require total hip replacement or show progressive osteoarthritis had been congruent after the index operation. The twenty-year Kaplan-Meier survival estimate, with conversion to total hip replacement as the end point, was 86.4% (95% confidence interval, 63.4% to 95.4%). The twenty-five-year survival estimate was 65.1% (95% confidence interval, 35.6% to 83.7%).

The Wagner spherical osteotomy prevented progression of osteoarthritis both clinically and radiographically in a high proportion of patients with residual hip dysplasia who were followed for a minimum of twenty years. Operative restoration of joint congruency is associated with a satisfactory long-term outcome in a very high proportion of cases.