Evaluation of acetabular versions after a curved periacetabular osteotomy for dysplastic hips

The purpose of this study is to investigate the early clinical and radiographic findings related to acetabular orientation after a curved periacetabular osteotomy (CPO). 106 dysplastic hips of 88 patients underwent CPO were investigated retrospectively with an average follow-up of 3.6 years. Conventional anteroposterior radiographs were used to measure the radiographic findings and range of motion were used for clinical evaluations. A significant improvement was noted in radiographic measurements including lateral centre-edge angle, acetabular index, and acetabular angle of Sharp. However, a high rate of postoperative acetabular retroversion was observed (62% hips) and a marked decrease in free flexion was noted. The Tönnis scale revealed a one-grade progression in most retroversion hips. Acetabular retroversion is a high risk factor leading to degenerative osteoarthritis of hip. Therefore, special consideration must be taken in surgical planning and careful intraoperative confirmation is required whilst manoeuvring the acetabular fragment in CPO.