Clinical outcomes of transposition osteotomy of the acetabulum in patients aged 50 years or older with hip dysplasia

Aims To clarify whether transposition osteotomy of the acetabulum (TOA) in patients aged ≥ 50 years with hip dysplasia provides clinical, radiological, and patient-reported outcomes comparable with those in younger patients. Methods Among 615 patients undergoing TOA between November 1998 and July 2019, 131 patients aged ≥ 50 years were propensity score-matched 1:1 to 131 patients aged < 50 years using sex, BMI, preoperative modified Harris Hip Score (mHHS), Tönnis grade, and lateral centre-edge angle. Matching was repeated with controls aged < 45 years. Clinical and radiological outcomes, joint survival, and patient-reported outcome measures (PROMs) were compared. Failure was defined as progression to Tönnis grade 3 osteoarthritis or conversion to total hip arthroplasty. Predictors of failure in patients aged ≥ 50 years were examined using Cox regression. Results In patients aged ≥ 50 years, the median mHHS improved from 62 (IQR 54 to 75) to 92 (IQR 84 to 96) (p < 0.001), with scores comparable with those in patients aged < 50 years (p = 0.685). Failure occurred in seven (5.3%) and ten hips (7.6%), respectively (p = 0.607), with similar ten- and 20-year joint survival (98% (95% CI 94 to 100) and 79% (95% CI 55 to 91) vs 97% (95% CI 89 to 99) and 72% (95% CI 51 to 86); p = 0.655). PROMs did not differ significantly between groups. When compared with patients aged < 45 years, patients aged ≥ 50 years had a lower median Hip disability and Osteoarthritis Outcome Score sport/recreation score (75 (IQR 56 to 81) vs 81 (IQR 63 to 94); p = 0.044) and more complications (12 (9.2%) vs 2 (1.5%); p = 0.013). Preoperative Tönnis grade 2 independently predicted failure (hazard ratio 8.67 (95% CI 1.36 to 55.34); p = 0.022). Conclusion TOA achieved long-term joint survival comparable with that in younger patients, supporting TOA as a joint-preserving option in this age group. However, the sport/recreation score was lower and complications more frequent than in patients aged < 45 years. Preoperative Tönnis grade 2 predicted failure, indicating that joint degeneration, rather than age alone, should guide patient selection. Cite this article: Bone Joint J 2026;108-B(11):1305–1314.