Ankle fusion is a permanent procedure and the most reliable treatment for relieving the pain of ankle arthritis. However, in addition to a major loss of ankle motion, the biomechanical alterations from ankle fusion can result in the worsening of arthritis in other joints, such as the knee and foot. Ankle joint-replacement surgery has made tremendous advancements in the past 10 years, with nearly 80 percent of modern implants still functional at 10 years after surgery. Ankle joint replacement usually is indicated for patients older than 55 who are not obese and who are moderately active. Repetitive-loading activities, such as running or tennis, place heavy wear on the implants and can cause them to wear out, so revision surgery is usually needed in five to 10 years.