Twenty-Year Clinical, Functional, and Radiographic Outcomes of Hip Resurfacing Arthroplasty: A Retrospective Cohort Study

Abstract

Background: Hip resurfacing arthroplasty (HRA) was developed as a bone-preserving alternative to conventional total hip arthroplasty (THA), particularly for young and physically active patients. However, concerns regarding metal-on-metal bearings have substantially restricted its use. This study evaluated the long-term clinical, functional, radiographic, and implant survivorship outcomes of HRA. Methods: This retrospective cohort study included all 53 consecutive primary HRA procedures performed at a single institution between January 2001 and December 2010. No patients were excluded or lost to follow-up. The mean age at surgery was 43.2 years (range, 18–56 years), and the mean follow-up was 20 years (range, 15–25 years). Clinical outcomes were assessed using the Harris Hip Score (HHS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Paired preoperative and final scores were analyzed only in the 47 patients who retained their HRA implant. Radiographic evaluation included implant fixation, radiolucent lines, osteolysis, component alignment, and heterotopic ossification. Implant survivorship was estimated using the Kaplan–Meier method, with revision of any component for any reason as the endpoint. Results: Among the 47 patients with retained HRA implants, the mean HHS increased from 31.3 ± 17.9 preoperatively to 95.3 ± 7.4 at final follow-up, while the mean total WOMAC score decreased from 65.9 ± 10.4 to 11.5 ± 3.5 (both p < 0.001). Six hips (11.3%) underwent revision to conventional THA: three for metallosis, two for femoral neck fracture, and one for persistent pain associated with acetabular radiolucency. One additional patient developed postoperative thrombophlebitis that did not require implant revision. Radiographic assessment of unrevised hips demonstrated stable component fixation without progressive radiolucency, clinically significant osteolysis, implant migration, or aseptic loosening. Kaplan–Meier implant survivorship was 88.7% (95% confidence interval, 76.5–94.8%) at approximately 20 years. Conclusions: In this selected cohort of predominantly young and active patients, HRA provided substantial long-term clinical improvement, with an HHS of 95.3 ± 7.4, a WOMAC score of 11.5 ± 3.5, and implant survivorship of 88.7% at approximately 20 years. Nevertheless, the 11.3% revision rate and complications associated with metal-on-metal bearings support restricting HRA to carefully selected patients and maintaining long-term clinical, radiographic, and metal-ion surveillance.