The investigators propose a mobility outcome study with a total of up to 500 ankle osteoarthritis subjects before and after surgery over the three years of the study. Ankle arthritis subjects will be recruited from patients at the VA Puget Sound Health Care System (Seattle, WA), Harborview Medical Center (Seattle, WA), Orthopedic + Fracture Specialists (Portland, OR), Orthopaedic Associates of Michigan (Grand Rapids, MN), and Twin Cities Orthopedics (Edina, MN) who have been diagnosed with end stage ankle arthrosis, are ambulatory, speak English, are cognitively intact, and between the ages of 18-80. Recruitment, informed consent procedures and the experimental protocol will be approved by the Institutional Review Board (IRB) at each study site.