Transposition osteotomy of the acetabulum for advanced-stage osteoarthritis of the hips

Background: Transposition osteotomy of the acetabulum (TOA) was the first periacetabular osteotomy in which the acetabulum was transposed with articular cartilage. TOA improves coverage of the femoral head and joint congruity. The purpose of this study was to investigate whether TOA is an appropriate option for treating osteoarthritis of the hips at the advanced stage by comparing it with matched control hips at the early stage. Methods: Between 1998 and 2001, TOA was performed in 104 hips of 98 patients. Altogether, 16 of 17 hips (94%) with osteoarthritis at the advanced stage were examined and compared with 37 matched control hips at the early stage. The mean age at the operation was 48 years (38-56 years), and the mean follow-up period was 88 months (65-107 months). Results: TOA corrected the acetabular dysplasia and significantly improved containment of the femoral head. Clinical scores were also significantly improved in both groups. In the advanced osteoarthritis cases, there was a tendency for abduction congruity before transposition osteotomy of the acetabulum to reflect the clinical outcome. Conclusions: TOA is a promising treatment option for advanced osteoarthritis of the hips as well as for patients at an early stage when preoperative radiographs show good congruity or containment of the joint.