11-Year outcomes in patients with metal-on-metal ASR hip arthroplasty

Background: We analysed the long-term revision rate, clinical outcomes and metal ion concentrations in blood over time in patients who had undergone metal-on metal Articular Surface Replacement (ASR) hip arthroplasty. Methods: A total of 38 patients (43 hips) were included: 24 patients (28 hips) underwent large-head total hip arthroplasty (XL THA), and 14 patients (15 hips) underwent hip resurfacing arthroplasty (HRA). The median follow-up time was 11 (range 7-12) years. Results: None of 15 HRA implants were revised. Nine of 28 XL THA implants (32%) in 8 patients were revised. The Co ion levels significantly increased in the XL THA group (p=0.009) over a median time period of 84 (25-97) months. Conclusion: The levels of Co ions in blood were higher in the patients who had undergone XL THA and increased significantly over time.