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. 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.