SHORT- TO MID-TERM RESULTS OF ROTATIONAL ACETABULAR OSTEOTOMY PERFORMED IN PATIENTS AGED 50 YEARS OR OLDER

Total hip arthroplasty (THA) with modern bearing surfaces has improved long-term outcomes. In an aging society where the average life expectancy reaches 80 to 90 years and healthy life expectancy continues to increase, even patients undergoing THA at the age of 50 should be considered to have an active period of 20 to 30 years or more. In patients over 50 years old, joint-preserving surgery may still be considered. The purpose of this study was to evaluate the mid-term results of rotational acetabular osteotomy (RAO) performed in patients aged 50 years or older. A total of 55 hips in 49 patients who underwent RAO for developmental dysplasia of the hip between 2014 and 2024 were included. The mean age at the time of surgery was 52.9 years. There were 43 female patients (49 hips) and 6 male patients (6 hips). The mean follow-up period was 6.4 years. Clinical evaluation was performed with the Merle d'Aubigne rating scale, and radiographic analyses included measurements of the center-edge (CE) angle, acetabular roof angle, and head lateralization index on preoperative, postoperative AP radiographs. Postoperative joint congruency was classified into four grades. In all cases, intraoperative hip arthroscopy was performed, and microfracture was performed if cartilage erosion was observed. The mean preoperative clinical score was 13.2, which improved to a mean of 15.7 at the time of the latest follow-up. The mean CE angle improved from 9.3°to 30°, the mean acetabular roof angle improved from 23.6°to 6.9°, the mean head lateralization index improved from 0.65 to 0.60 postoperatively. Postoperative joint congruency was excellent in 22 hips, good in 33 hips. Eight patients (9 hips) had radiographic OA progression, and two patients (2 hips) were converted to THA. Kaplan-Meier survivorship analysis, with radiographic OA progression as the end point, predicted survival of 75.6% at 10 years.