Ankle arthritis is a condition where the shock absorbing cartilage that lines the joints has worn away and bone rubs against bone. It causes pain and stiffness.

Up to 30,000 people go and see a specialist each year because of pain from ankle arthritis. The pain from ankle arthritis can be disabling and make walking difficult and can affect quality of life as much as hip arthritis and heart failure.

Unlike hip or knee arthritis which is usually genetic, the commonest cause of ankle arthritis is following injury, such as ankle fractures or severe ankle sprains but it can sometimes up to 20 years or longer for arthritis to set in. Other causes include rheumatoid arthritis, gout or infection.

The good news is that most patients do not require surgery. Weight loss, modifying activities, support braces, analgesia, and physiotherapy helps most patients. Once the non-surgical treatments have been tried and failed then surgery can be considered.

The two main surgical options to treat ankle arthritis are total ankle replacement and ankle fusion. Surgeons consider many factors, such as age, mobility, and severity of deformity, in recommending ankle fusion or replacement.

In a total ankle replacement, the damaged bone ends are removed and resurfaced with metal implants and then a plastic liner allows gliding motion between them. It is very similar to a knee replacement or hip replacement which is more commonly known.

In an ankle fusion, a surgeon removes the damaged surface of the ankle bones and then puts metal screws, plates or staples across the ankle so that there is no ankle motion. There are 30 other joints in the foot which continue to move, so although the ankle is fused, this does not mean you lose all ankle and foot motion.

In an ankle replacement the joint is mechanical and so over time the implants can loosen and become painful. The current modern implants have a failure rate of about 1.5% per year, which means that after 10 years 15% may have had to be revised. Another way of looking at this is that after 10 years 85% of ankle are still functioning.

In an ankle fusion, the 30 joints around the fused ankle remain mobile and this explains why in a patient with healthy surrounding joints, gait and function may be normal. However, these joints are put under more stress to compensate for the stiff ankle and eventually they can start to wear and become painful and stiff. After 10 years studies have shown that most patients will have Xray evidence of wear and tear in the other joints, although not all will have symptoms.

In medicine new treatments are tested using a randomised trial in which participants can receive either the new treatment or the conventional treatment assigned to them randomly like tossing a coin (heads or tails). Unlike drug trials, such studies of surgical treatments are more difficult to run, because both treatments are already available on the NHS and it is really difficult for patients to decide which treatment is better for them.

The TARVA study was a randomised study of ankle replacement against ankle fusion in patients aged between 50-85 with severe ankle arthritis in which their surgeon felt they were suitable for either treatment but did not know which surgery the patients would prefer. Patients will be followed up for up to 10 years and will also help determine which treatment is more cost effective for the NHS.

Because the treatments are so different, one allowing motion at the ankle joint and one removing motion, it is almost impossible for patients to choose between treatments and although both surgeries are effective, most studies comparing them have been observational. The surgeons wanted to produce some high quality information to help patients and their treating surgeons determine which operation is best.

Patients with ankle osteoarthritis, aged 50 to 85 years, who the treating surgeon believed to be suitable for either ankle replacement or ankle fusion. Patients were recruited between 6 March 2015 and 10 January 2019 by investigators in outpatient clinics at 17 sites in the United Kingdom.

After recruitment and informed consent, patients were randomly assigned to ankle replacement or fusion. Surgeons who screened and recruited patients were unaware of treatment assignments.

Patients answered a standardized questionnaire about walking and standing before and 1, 2, 5 & 10 years after surgery. Authors compared the difference between the two groups. They also compared all adverse events and complications.

The walking and standing scores improved with both ankle fusion and ankle replacement at 52 weeks. Although scores with ankle replacement improved slightly more than ankle fusion, overall, the difference was not clinically or statistically significant. A fixed bearing ankle replacement however did seem to outperform ankle fusion especially where there was existing wear and tear of the surrounding joints. Adverse event rates were similar, but ankle replacement had more problems with wound healing and nerve injuries and ankle fusion had more clotting and nonunion of the bone. Seven percent of patients with ankle fusion had nonunion of the bone that caused pain.