The use of total ankle replacements is increasing as an alternative to arthrodesis that allows patients to maintain both mobility and function concomitant with pain relief. Their success, however, remains mixed mostly attributed to the interaction of design geometries and the complexity of ankle joint motion. This has been exemplified by failures of designs with excessive constraint or insufficient material durability leading to loosening and wear. The expectation of these failures makes paramount the evaluation of anticipated device performance, particularly long-term fatigue and wear characteristics, prior to widespread clinical use. The recent United States Food and Drug Administration (USFDA) clearance of the first mobile bearing total ankle replacement represents the culmination of extensive pre-clinical and clinical evaluations. This handout describes the wear characteristics of a three-part mobile total ankle replacement during 10 to 20 years of simulated walking in a novel, multi-axial gait simulator with comparison to clinical retrievals. These results are useful in demonstrating safety and effectiveness of this device and also present a pre-clinical evaluation methodology for future ankle designs.