Comparison of Outcomes Between Fixed and Mobile-Bearing Total Ankle Arthroplasty: A Systematic Review and Meta-Analysis

Category: Ankle Arthritis; Other Introduction/Purpose: End stage ankle osteoarthritis is a significantly debilitating pathology that is most commonly preceded by trauma. The emergence of 3rd and 4th generation total ankle arthroplasty (TAA) implant designs have led to more favorable outcomes compared to its predecessors. TAA implants can be broadly divided into fixed bearing and mobile bearing implant designs, however, no consensus has been reached regarding the optimal TAA implant design for the management of end stage ankle arthritis. The purpose of this systematic review and meta-analysis was to compare outcomes between patients who received fixed bearing TAA implants and mobile bearing TAA implants. Methods: During January 2023, the PubMed, Embase and Cochrane library databases were systematically reviewed to identify clinical studies comparing outcomes between patients who underwent fixed bearing TAA implant and patients who underwent mobile bearing TAA implant for the management of end stage ankle arthritis. Data regarding surgical characteristics, subjective clinical outcomes, radiographic outcomes, failure rates and complications were extracted and analysed. Results: Overall, 13 studies were included in this review. In total, 2793 patients underwent mobile bearing TAA implant and 2241 patients underwent fixed bearing TAA implant for the management of end stage ankle arthritis. No difference existed between the 2 cohorts with regards to post-operative subjective clinical outcome scores nor radiological outcomes. The mobile bearing TAA implant cohort was associated with higher complications (RR = 1.4710; [1.0375-2.0857]; p = 0.0373) and failures (RR = 1.3916; [1.2038 - 1.6086]; p = 0.0032) compared to the fixed bearing TAA implant cohort. Conclusion: This systematic review and meta-analysis found no difference in subjective clinical outcomes and radiological outcomes between patients who underwent mobile bearing TAA implant and fixed bearing TAA implant for the management of ankle arthritis. Interestingly, the mobile bearing TAA implant cohort was associated with higher complications and failures compared to the fixed bearing TAA implant cohort. Due to the marked under-reporting of data and significant heterogeneity between the included studies, further high quality research is warranted to determine the optimal TAA implant type for the management of end stage ankle arthritis.