Objective: To study the occurrence and radiograph features of the acetabular retroversion in hip dysplasia, and to evaluate the effects on the retroversion by the traditional maneuvers in the periacetabular osteotomy.
Methods: Bernese periacetabular osteotomy was performed to 45 continuous dysplastic hips (43 patients) from December 2001 to November 2003. There were 37 female (39 hips) and 6 male (6 hips), average age was 28.9 (range, 15-45). The diagnosis of acetabular retroversion was based on the "cross-over" and "posterior wall" signs on the standard radiographs of the patients pre- or postoperatively.
Results: Among total 45 hips, the "cross-over" sign was positive in 8 hips, whereas including the "posterior wall" sign positive in 5 hips. The occurrence of retroversion was 17.8%. And the cross-over points were located within the superior 1/3 of the acetabulums in all cases. After the osteotomy, all the cross-over points moved to the inferior 1/3 of the acetabulums, and the "posterior wall" sign was seen in all 8 cases.
Conclusions: Approximately one sixth of the patients with acetabular dysplasia have retroversion in which the superior 1/3 of the acetabulum faces posterolaterally. The retroversion can be identified with the standard AP pelvic radiographs. With the traditional maneuvers in periacetabular osteotomy, the retroversion will be aggravated in these patients.