Factors Contributing to the Progression of Osteoarthritis After Rotational Acetabular Osteotomy: A Study of 183 Hips With a Median Follow-Up Period of 14 Years.

Abstract

Rotational acetabular osteotomy (RAO) is a joint-preserving procedure that improves femoral head coverage. This procedure is expected to counteract the progression of secondary osteoarthritis of the hip (OA) in young patients who have developmental dysplasia of the hip (DDH). However, postoperative OA progression still occurs owing to multiple factors. Therefore, we aimed to investigate the factors contributing to postoperative OA progression using patient cohort data with a median follow-up period of 14 years after RAO surgery for DDH without severe OA. The records of patients who underwent RAO for DDH who had Tönnis grades 0 and 1 were retrospectively reviewed. We calculated the survival rates by setting total hip arthroplasty and progression to Tönnis grade 2 OA as the endpoints. The associations between patient background, preoperative OA stage, postoperative acetabular coverage, and OA progression were investigated. A total of 160 patients and 183 hips (Tönnis grade 0, 112 hips; grade 1, 71 hips) were included in the final analysis. The median follow-up time was 14 years. The 20-year survival rates with total hip arthroplasty as the endpoint were similarly good at 86.4% in both Tönnis grade 0 and 1 OA groups. However, in these groups, the survival rates with progression to Tönnis grade 2 OA as the endpoint were 74.6 and 49.3%, respectively. Age at the time of RAO, preoperative OA stage, and body mass index(BMI) were predictive factors for OA progression in the univariate analysis. In the multivariate analysis, BMI was the only independent predictive factor for OA progression. Our RAO cohort with a median follow-up period of 14 years demonstrated good survival rates in patients at the preosteoarthritis stage and in patients at the initial stage of DDH. In the multivariate analysis, high BMI was independently associated with OA progression after RAO. Level III.