Since the late 1800s, individuals who suffered severe arthritis of the ankle have been treated with surgery that has entailed fusing the bones of the ankle together to eliminate the arthritic joint. This effectively treated the pain of the arthritis, but left the ankle joint immobile. The other large, weight-bearing joints of the body - the hip and knee - used to be treated in this same manner using a fusion, but since the 1970s have largely been treated by joint replacement.
The procedures of joint replacement for the hip and knee have become so successful that it has been categorized as one of the most important medical breakthroughs of this century. Despite this, replacement of the ankle joint has been less successful until just recently.
In May 2009, the FDA approved a newly designed, three-part, cementless ankle replacement that was originally designed in Denmark and called the Scandinavian Total Ankle Replacement (STAR). This approval came after a seven-year analysis of the STAR ankle in a study performed at 10 institutions in the United States with more than 600 patients involved. As one of the investigators in this study, I found the STAR ankle to be very effective in treating ankle arthritis in certain patients, and so my colleague, Dr. Roger Mann, and myself introduced this ankle replacement procedure at Vail Valley Medical Center in late 2009.
The best patients for the STAR procedure are older individuals (usually above age 65) who have arthritis of the ankle that is caused by osteoarthritis, inflammatory arthritis, or post-traumatic arthritis. There are certain conditions that make joint replacement less desirable such as a history of joint infection, neuropathy, or severe deformity. For the younger individual with arthritis of the ankle, ankle arthroscopy or ankle fusion may be better alternatives. Those ankle arthritis patients who undergo joint replacement with a STAR can generally be expected to resume walking, hiking, road biking, skiing, and playing golf once their ankle is fully rehabilitated, but they cannot engage in high impact activities like running and jumping.
The STAR ankle is one of four ankle prostheses being used in the United States today. The other replacements are fixed bearing implants or two-part designs. They include the Agility Ankle made by Depuy, the Salto Talaris ankle made by Tornier, and the Inbone Ankle made by Wright Medical. The STAR is the only one of the four approved by the FDA as a mobile-bearing design and for use without bone cement. It replaces the worn-out surfaces of the tibia and the talus with metal implants and a high-density polyethylene mobile bearing is placed between the metal pieces to provide a moveable surface.
Dr. Tom Clanton is an orthopedic ankle surgeon with the Steadman Clinic in Vail and is the director of foot and ankle sports medicine at the clinic.