Ankle Arthritis

What is arthritis?

All the joints in the body are covered with a smooth covering that is called articular cartilage. This articular cartilage is a tough and smooth surface which allows the joint to move freely. If the joint surface is damaged then the joint does not move freely. These movements become stiff and may be painful. This damage to the cartilage is called arthritis.

What is the cause of arthritis?

In many cases the cause of arthritis may not be known. The cartilage damage may be caused by injury such as after a broken ankle or even an ankle sprain. Sometimes there is a family history of arthritis where family members have arthritis of many joints such as fingers, hips or knees. However if you have arthritis in your ankle your children are not necessarily at risk of having the same problem. There are other forms of arthritis associated with inflamed joints. The articular cartilage can be damaged with these conditions.

How is the diagnosis made?

The assessment involves taking a careful history and clinical examination. X-rays of the ankle are usually required. These are usually taken weight bearing to assess the ankle joint with you standing. Further imaging can be useful such as MRI scanning. A diagnostic injection of local anaesthetic and steroid can be useful in determining if the ankle joint is a source of pain.  

Treatment of ankle arthritis – non surgical

Many things can be done to ease your ankle pain. Losing weight can reduce the forces through your ankle and this may relieve some of the pain. Maintaining fitness by performing activities that do not involve impact on the ankle may help. These activities include swimming and cycling.
An arthritic ankle is stiff and this alters the walking style. I have many patients that have been helped by shoes which have a rocker bottom. (Please see rocker bottom shoe information sheet).
Taking regular painkillers such as paracetamol and ibuprofen may help to improve your ankle symptoms. Some of my patients take regular glucosamine and chondroitin sulphate tablets. These are available over the counter at most supermarkets or at health food shops. They are not available on prescription because the medical evidence is weak but I have many patients who have been helped by them. It is probably worth trying them for a period of 3 months keeping a diary of symptoms so you can tell if they are working.
Injections with steroid and local anaesthetic can help. The effect of the steroid is unpredictable and may last for a few days, a few weeks or months. Some patients have long term pain relief. The steroid is not a treatment of the arthritis but a method of relieving pain only.

Treatment of ankle arthritis – arthroscopic debridement

In the early stages of ankle arthritis, an assessment of the ankle and a tidy-up with a small telescope may help. With the arthritic process the ankle develops extra bone which restricts the ankle movement. These can be removed at the time of the arthroscopic procedure. If there is damage to the joint surface this can be tidied up at the same time. This is called a debridement. Although this does not cure the ankle arthritis, there may be considerable pain relief from this procedure.

Treatment of ankle arthritis – ankle arthrodesis

This is a good procedure to relieve pain when the ankle joint surfaces are worn out. The ankle is painful because the smooth articular surfaces are not smooth and the rubbing of these joints causes pain. If the joint is permanently stiffened by allowing the two bones to fuse then because the ankle joint does not move hence no pain is caused. This stiffening operation is called an ankle arthrodesis or fusion.
The fusion operation may be performed after arthroscopic assessment and the joint surfaces prepared using special equipment. Sometimes it is not possible to perform this arthroscopically and in this case the ankle may be fused using larger wounds. After the joint surfaces are prepared, the ankle arthrodesis is stabilised using either 2 or 3 screws.

Post-operative course after ankle arthrodesis

After ankle arthrodesis, the lower limb is stabilised for 6 weeks in plaster. The plaster is below the knee.  During this time you will be non-weight bearing and will have to use crutches. The first 2 weeks will be spent in a back slab plaster which allows for swelling. At 2 weeks the back slab will be removed and you will have stitches removed. From week 2 to week 6 you will be in a solid plaster.
At week 6 you will have your plaster removed and an X-ray will be taken. If satisfactory then you will be placed into a walking boot. This boot is like a plaster and will give you similar support but the boot can be taken off at night time. You can bathe without the boot on. You can start to mobilise partial to full weight bearing in the boot as tolerated.
At 12 weeks you will be seen in clinic and you will have an X-ray taken. If all is well you  can then wean yourself off the boot. This means starting to walk using normal shoes inside the house but using the boot for longer walks. As time passes and you feel more confident then you can use the boot less.

Alteration in walking and shoe wear after arthrodesis

The arthrodesis is an operation that converts a stiff painful joint into a stiff painless one. Pain will be relieved and this will improve your walking. However the ankle joint will be permanently stiff and this will alter the way you walk.
You may encounter difficulty getting shoes on and off. Some of your shoes may need to be modified. The ankle will be stiff and this will alter your walking style. Many of my patients have found that using rocker bottom shoes greatly improves the walking style and efficiency.

 

Treatment of ankle arthritis – ankle replacement

The worn out ankle surfaces may be resurfaced using an ankle replacement. These worn out surfaces are replaced with metal and plastic ones. This provides a smooth and pain free surface. The ankle replacement will not last forever. Most will last 6 – 8 years after insertion.
Not everyone is suitable for this operation. If there is too much deformity of the ankle as a result of long term arthritis then the ankle replacement is not suitable. In this situation an ankle arthrodesis is the best option.
Young patients with high physical demands may not be suitable for this procedure as the ankle replacement will wear out. If you think of an ankle replacement as a car tyre, the more mileage you do in your car, the quicker your car tyre will wear out. So if you perform an ankle replacement in a young and active patient it will wear out a lot quicker than a less active elderly patient with less physical demands.
The worn out ankle replacement is difficult to revise and further ankle replacement is difficult if not impossible. Hence when an ankle replacement fails the next procedure to try is an ankle arthrodesis. This ankle arthrodesis is very difficult to perform so in young patients who are likely to wear out the ankle replacement quickly, an ankle arthrodesis is more likely to give long term pain relief without the need for a second procedure.

Ankle replacement operation

The ankle replacement is performed through a large cut at the front of the ankle. The bone surfaces are carefully prepared and the metal implants are inserted first. A plastic liner is then placed between the metal surfaces and the whole ankle is X-rayed. If satisfactory then the ankle wounds are then closed and a Plaster of Paris is applied.

Post-operative course after ankle replacement

For the first 2 weeks you will be non-weight bearing in a cast. At 2 weeks you will have the cast removed and stitches removed. After that you may need to be in a cast for a further 2 – 4 weeks or alternatively a special boot. Weight bearing may be commenced depending on the individual patient. At 6 weeks post operatively you should be mobilising full weight bearing without any protection. You will need annual check-ups after that with x rays.

Risks of the surgery:

Infection

This is an uncommon complication. Most infections are superficial and may be treated with a short course of antibiotics. If the infection is deep then an admission to hospital and further surgery may be required. This is an uncommon occurrence.

Nerve Injury

A small nerve about 1mm in diameter lies just beneath the skin. This may be damaged during the approach to ankle. This may lead to permanent damage to the nerve with permanent numbness on the top of the foot.

Pain and Swelling

It is not surprising that it may take several weeks or months for your foot and ankle to settle down after this extensive surgery. Many patients experience pain and swelling especially in the first few weeks. Rest and high elevation are required to keep these at a minimum.

Deep vein thrombosis and pulmonary embolus

After any lower limb surgery there is a risk of a clot on the leg (deep vein thrombosis - DVT) and clot on the lung (pulmonary embolus - PE) . After this procedure you will be mobile and so the risk of these complication are small and prophylaxis is not required. If you have had a previous DVT or PE you may be at increased risk.
A risk assessment will be performed pre-operatively. The majority of people undergoing this surgery are at a low risk and do not require any prophylactic medication to reduce the risk of these clots. If your risk is moderate or high prophylactic treatment may be necessary.

Non-union

After a fusion operation the bones may not heal and become solid. This is called a non-union. This has a higher occurrence is people who smoke. If this occurs then a further operation may be required. If you smoke you are at higher risk of this complication. Stopping smoking preoperatively will reduce the risk of this complication.

Failure after ankle replacement

The ankle replacement will fail eventually. Pain is the resulting symptoms. Revision to another ankle replacement is often not possible and so an ankle arthrodesis or ankle fusion is necessary. This is often more difficult and requires bone grafting.