Total ankle replacement surgery, known as prosthesis, is a major procedure most commonly performed for patients with advanced ankle osteoarthritis. The aim of an ankle replacement is to eradicate persistent pain and preserve ankle mobility.
Although hip and knee replacements are commonplace procedures, attempts to deliver the same solution for the ankle have been problematic. Devices have frequently loosened and failed, due to the pressure placed on the ankle.
The ankle is a particularly complex joint to replace because it needs to flex and rotate and due to its size and shape, the ankle receives more strain than any other joint in the body.
However the new generation of total ankle replacements integrate much more effectively into the ankle joint with much improved results.
Who needs the surgery?
This is a major procedure which is only considered for patients with advanced arthritis or severe damage to the joints following trauma.
Joint wear and tear between the surfaces of the shin bone (tibia) and ankle bone (talus) will be extensive, causing pain even while resting and preventing normal daily activities.
The best results from total ankle replacement have been recorded in older patients, typically aged over 60, because they put their ankles under less stress than a younger person. Some younger patients have had good results from this type of surgery, but it remains to be seen how long the joint replacement lasts.
A younger or particularly active person may consider an ankle fusion operation as a more appropriate alternative.
When considering ankle replacement surgery, it is also important that there is good movement of the joint and no significant foot deformity.
How does it work?
Ankle replacement involves replacing the natural surfaces of the ankle joint which have degenerated with an artificial cover known as prosthesis.
The ankle replacement has three components. Two of the components cover the joint and in the middle there is a third, mobile component. This allows for greater movement and reduces the stress between the bone and the implants.
The component which covers the part of the ankle joint known as the tibia is flat. It is integrated into the bone with a short stem. The component which covers the part of the ankle joint known as the talus is curved and fixed into place with pegs. All the components are covered in a bioactive coating which encourages the patient’s own bone to grow into the artificial fixtures.
This type of operation allows the patient to preserve the movement that they have and gain a few degrees. Its success lies in the way that the ankle replacement integrates into the natural bone. The use of a mobile plastic bearing means the prosthesis is under much less stress and will stay in place a lot longer than the old two-part ankle joint replacements.
How long will it take to recover?
A day after your surgery, you will be encouraged to take a few non-weight bearing steps with crutches under guidance of a physiotherapist. Your mobility on crutches and pain control will improve and you are likely to be discharged from hospital two to three days after surgery. You will be wearing a lightweight cast and walking confidently with crutches.
For the first six weeks after surgery, you will work with a physiotherapist on improving mobility and begin to partially weight bear. Your cast will be removed between four and six weeks following surgery, depending upon your recovery.
For the first six months following surgery, activities such as tennis and aerobics should be avoided. Six months post surgery, you should have normal joint mobility and be able to resume normal daily activities. However, it can take more than a year before you are fully recovered and the ankle replacement surgery can be completely evaluated.