All about ankle replacements

In this latest interview, orthopaedic surgeon Mr Hisham Shalaby tells us all you need to know about ankle surgery.

What is ankle replacement surgery and how does it work?

Ankle replacement is a surgery to substitute the damaged arthritic surface of the ankle joint with an artificial joint. The replacement joint is usually formed of two metal components and a plastic insert in between. This procedure addresses the 3 main problems facing ankle arthritis patients:

1. the pain, which is addressed because the surface of the joint is replaced
2. the deformity, which is addressed by correcting any deformity as part of the procedure
3. the instability, which is what happens when the joint is misaligned or when the ligaments are damaged. The surgeon will do soft tissue balancing during the procedure, therefore restoring stability

Who is a candidate for ankle replacement surgery?

Patients with advanced ankle arthritis, the majority of whom are usually post-traumatic patients. Ideally, they shouldn’t be too young and most ankle replacements are offered to patients over the age of 60, but gradually, younger patients are now being offered replacements.

Ideally, there shouldn’t be any history or any clinical signs to suggest infection, because infection is a contra-indication of this procedure. Obviously, the patients will normally be in pain, and they would have tried conservative treatment but the outcome wouldn’t be satisfactory for them, and therefore they would have asked for a much more definitive treatment, such as an ankle replacement.

What are the benefits of ankle replacement surgery compared to other treatments?

So, the main treatment that ankle replacement is compared with is ankle fusion. This is the other treatment that we offer for patients with severe ankle arthritis. The main difference between these two procedures is that with an ankle replacement, there is a shorter recovery period and a shorter period of immobilisation. Furthermore, studies have shown that patients with an ankle replacement walk with a more natural gait compared to those with ankle fusions. Many patients would prefer not to have their ankles fused and they want to keep movement in the ankle.

However, ankle replacement is not an operation for movement; it is an operation for pain management. Some patients will get a lot of movement after, but others will get very little movement. Regardless, patients are happy that the pain is significantly better. 

Having said that, even if the range of movement is not significant after ankle replacement, a small range of movement can effectively protect the neighbouring joint – because if a joint is fused, then all the stress and pressure gets transferred to the next joint down. Thus, a very common complication of ankle fusion is arthritis in the neighbouring joints that can present years after the fusion procedure.

What is the recovery process like after ankle replacement surgery?

After an ankle replacement, patients are usually in a boot for four to six weeks. After two weeks, they will have to return to the doctor to remove the sutures, and again at six weeks to get X-rays will which check if everything is fine. Patients should start physical therapy after the second week, when their wounds have healed, and the physical therapy protocol will have been developed for rehabilitation prior to the procedure. Patients will start with gait training, progress to core muscle strengthening, range of movement exercises and calf stretches, and gradually, they will begin to introduce their day-to-day activities in small increments. At six weeks, they would be usually walking without the boot – though they may have assistance with crutches – and doing things like swimming, and maybe a static bike. Activities like golf can be started with a couple of holes around the 12-week mark, and more aggressive activities like hiking, for example, usually happen after six months.

What are the potential risks and complications associated with ankle replacement surgery?

Ankle replacement surgery is a major joint replacement, so like hips and knee replacements, there are risks linked to this procedure. For example, the swelling will last for a long period of time. There is a small risk, between four to five per cent, of superficial wound infection, which might demand some antibiotics or dressings. Deep infection is a bit more serious, but much rarer, and happens in less than one per cent of cases. Numbness in the calves can happen as well. Injury to major nerves and vessels, again, is very rare, way below one per cent. There is also the risk of having a blood clot in the leg, but again in way less than one per cent of patients. Very rarely, a clot can travel to the lungs (pulmonary embolism) and become very serious.

Other risks that are inherent in this procedure are things like malalignment. Doctors do their best to get that alignment right and measure angles, and now they do a preoperative navigation of these ankles so that it is very accurate, but again, sometimes the alignment can be off a few degrees or so. 

Another thing that `patients have to appreciate is that any joint replacement can ultimately come loose. Loosening means that the bond between the ankle replacement and the bone starts to break, and the joint starts to rattle a little bit, which makes the joint painful. We call it the survivorship of the implant. The current survivorship of ankle replacement is something between 90-95% at 10 years. This means that after a period, the joint can become a bit loose, and if it is loose it can become painful. and if it’s bad enough patients might need revision surgery. 

If you would like to know more about ankle replacement surgery, you can consult with Mr Shalaby via his Top Doctors profile