Comparing Ankle Fusion to Ankle Replacement

End-stage ankle arthritis (ESAA) is a debilitating condition associated with severe pain, dysfunction, and reduced quality of life. Many patients with ESAA have difficulty walking for even 100 feet or up a single flight of stairs. Patients seeking surgery for ESAA have two primary treatment options: ankle arthrodesis (i.e., ankle fusion) and ankle arthroplasty (i.e., ankle replacement). Few studies have directly compared the effectiveness of these two procedures, and no randomized controlled trials (RCTs) have been performed. The investigators will compare the following in subjects undergoing ankle arthrodesis and ankle arthroplasty before surgery, and post-surgery at 3 and 6 months, and on an annual basis up to ten years. 1. Overall physical function and ankle specific function 2. Ankle pain intensity and interference with activities 3. Activity levels 4. Overall general health 5. Post-surgical complication rates The investigators will also identify prognostic factors that are predictive of higher physical function, ankle specific function, reduced pain, improved general health, and overall patient satisfaction.