ANKLE FUSION

Ankle Fusion is an operation to “fuse” or stiffen the ankle joint. Ankle fusions are done for two main reasons:

(1) arthritis of the joint, because of a previous injury that has damaged the joint, a generalised condition such as osteoarthritis or rheumatoid arthritis, or because the joint is just wearing out for some other reason

(2) severe deformity of the rear part of the foot, such as a flat foot, high-arched or “cavus” foot, a club foot or other deformity, in which the ankle joint is also deformed, unstable or damaged.

It is now possible to treat some arthritic ankle joints by replacing the joint, in the same way as arthritic hips and knees can be replaced. However, this is only suitable in older patients without major foot deformities, or people with rheumatoid arthritis or similar diseases. It would not be suitable if:

• you are young (usually under 45) or very physically active
• you have a severe foot deformity
• your ankle is very unstable
• you have had infection in the ankle or the bones around it
• the bone under the ankle (the talus) has collapsed

In these situations a fusion would be advised instead. If you have a severe foot deformity you may be advised to have this corrected at the same time as your ankle fusion by fusing other joints and/or breaking and realigning the foot bones. This would be discussed at the same time as your ankle fusion and we have other information sheets which give information about major foot fusions.

We are sometimes asked if a fusion can be changed to an ankle replacement later. This is not possible, as the foot becomes too stiff for an ankle replacement to work.

We often inject local anaesthetic or steroid into damaged joints, before any surgery is considered, to see whether this helps the pain. In some people, this gets rid of the pain and surgery is not necessary. In others, pain relief does not last but the results of the injection helps us to decide which joints to fuse.

Ankle fusion in this hospital is nearly always performed by an arthroscopic (telescope) technique. This involves inserting a telescope into the ankle and by using specialised instruments we can remove the joint surface to allow the two bones to heal together. The bones are held rigidly by two screws inserted from the inner aspect of the leg just above the ankle joint. The operation will involve therefore 4 small cuts of approximately 1cm around the ankle.

Some people who have foot deformities have a tight Achilles tendon (“heel cord”), or weak muscles, or both. The Achilles tendon may be lengthened during surgery by making three small cuts in the calf and stretching the tendon.