Periacetabular osteotomy of the hip: an 8-year follow-up of 96 consecutive cases

Introduction A periacetabular osteotomy (PAO) is a joint-preserving surgical option for treatment of acetabular dysplasia. The procedure aims to prevent, or at least delay, the development of osteoarthritis, and subsequent need for total hip arthroplasty (THA). The conversion rate to THA differs widely in the literature, but most of the studies have few patients, and the follow-up time is often short for THA as an endpoint. The aim of this study was to evaluate the long-term outcome after PAO surgery with the rate of conversion to THA as the primary outcome. Materials and methods Patients ≥18 years that underwent a PAO operation at the Karolinska University Hospital in Stockholm, Sweden from 2006 to 2022 were included. Radiological signs of hip osteoarthritis, and the lateral center-edge angle (LCEA) was calculated on pre- and postoperative radiographs or CT-scans. The national Swedish Arthroplasty Register was used to find cases who had a secondary operation with THA. Results The number of cases included was 96. Median age was 30 (18–46) years, and 84% (n = 81) were females. Median follow-up time was 99 (17–227) months (8 years). A total of 21 (22%) cases had a secondary THA. Cox regression analyses identified that age ≥ 30 years was associated with THA in both uni- (HR 2.8, CI 1.1–7.3) and multivariable (HR 5.2, CI 1.5–18) analyses. Preoperative osteoarthritis (Tönnis grade 2) was associated with THA in multivariable (HR 24, CI 2.1–247) analysis. A total of 49 (51%) cases were reoperated due to other reasons than THA. The most common reason was extraction of screws (n = 39, 41%). Forty-four (43%) patients had an adverse event. The most common was a transient nerve injury. Conclusions The PAO procedure is a suitable option in young patients with symptomatic dysplasia of the hip in order to avoid, or at least delay, hip arthroplasty.