Hindfoot Arthritis

What is it?

The hind foot joints refer to the back of the foot around the ankle, subtalar and talonavicular joints. There are many forms of arthritis, but osteoarthritis is the most common.

Why does it occur?

Arthritis of these joints can occur because of a previous injury that has damaged the joints; a generalised condition such as osteoarthritis or rheumatoid arthritis, or because the joint is just wearing out for some other reason such as severe deformity of the foot, like flat foot, a club foot or other deformity.
Sometimes injections and orthotics can help manage the pain. Surgery can also correct the problem by breaking and reshaping the bones, but in other cases it is best to stiffen the joints in the corrected position, particularly if the joints are already stiff or the foot is weak.
We sometimes 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 need surgery.

What does it involve?

A cut is made on one or multiple sides of the foot, about 4-5 cm long. The joint is opened up and the joint surfaces (cartilage) removed and, if necessary, reshaped to correct a deformity. The joint is then put in the correct place and fixed together with screws, plates or staples passed through the main cut.

It is sometimes necessary to put some extra bone into a fusion to get it to heal and to fill any gaps in the fusion left by correcting deformity. Often this extra bone can be obtained from the bone that is cut out to prepare the fusion. Sometimes there is not enough bone and more needs to be obtained from other bones like the heel bone, or artificial bone graft may be used.

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 lengthening the calf muscle.
Weak muscles may be compensated by moving the tendons of normal muscles to do the work of the weak ones. This might be done at the same time as a fusion, or it may be best to do it at another operation. These "tendon transfer" operations are planned individually and your surgeon and physiotherapist will discuss this with you.
Some people with deformities of the foot also have deformed toes. Again, these may be corrected at the same time or at a later operation.

How long would I be in hospital?

This type of surgery is nearly always day surgery

Will I have to go to sleep (general anaesthetic)?

The operation can be done under general anaesthetic (asleep). Alternatively, an injection in the back of the knee can be done to make the lower leg go numb while the patient remains awake. Your anaesthetist will advise you about the best choice of anaesthetic for you.

Will I have a plaster on afterwards?

You will need to wear a plaster from your knee to your toes until the joints have fused - usually 6 weeks. For the first six weeks you should not put any weight on your foot as it may disturb the healing joints. You will then be transferred into a cam walker (fracture boot) for a period of time.

How soon can I...

Walk on the foot?

As explained above, you should not walk on the foot for six weeks after surgery. You can then start walking, usually initially with crutches, for a period of time usually 4 weeks.

Go back to work?

This will depend on the type of work you do and whether you can work from home.

Play sport?

After you come out of the cam walker you can start taking increasing exercise. Start with walking or cycling, building up to more vigorous exercise as comfort and flexibility permit. Obviously, the foot will be stiffer after surgery and you may not be able to do all you could before. However, many people find that because the foot is more comfortable than before surgery they can do more than they could before the operation. Most people can walk a reasonable distance on the flat, slopes and stairs, drive and cycle. Walking on rough ground is difficult after a fusion because the foot is stiffer. It is unusual to play vigorous sports such as squash or football after a hindfoot fusion but running in a straight line is possible.

What can go wrong?

The main problem is the swelling of the foot, which may take many months to go down fully, and some people’s feet always remain slightly puffy. You may find that only trainers are comfortable for several months. Keeping your foot up, applying ice, or wearing elastic stockings may help to keep the swelling down. Swelling is part of your body’s response to surgery rather than the operation "going wrong," but it is a nuisance to many people who may be concerned that something has indeed gone wrong.

The most serious thing that can go wrong is infection in the bones of the foot. This only happens in about 1% of people, but if it does, it is serious, as further surgery to drain and remove the infected bone and any infected screws or pins will be necessary. You may then need yet more surgery to get the foot to fuse in a satisfactory position. The result is not usually as good after such a major problem as if the foot had healed normally.

About 5-10% of hindfoot fusions do not heal properly and need a further operation to get the bones to fuse—basically another fusion. This is more common in smokers, so we urge patients to stop smoking after surgery until the joint has fused. Minor infections in the wounds are slightly more common and normally settle after a short course of antibiotics. Sometimes the cuts are rather slow to heal. This usually just requires extra dressing changes and careful watching to make sure the wound does not become infected.

There is a small risk of developing a deep venous thrombosis (clots in the veins of the leg) after this type of surgery. We will assess if your individual risk is high enough for you to need blood-thinning medication while you are in plaster.

Sometimes screws or pins can be tender and painful. If this happens, they can be removed. We find that about 20% of our patients need a metalwork taken out. This is a relatively minor procedure, and you do not need to go into a cast afterwards.