ANKLE REPLACEMENT

What is ankle arthritis?

The ankle joint is made up of the tibia, fibula and the talus. It allows the foot to move up and down during walking and running. The ankle joint has a smooth layer of cartilage which allows the joint to move freely and smoothly.

Arthritis is a condition in which the cartilage layer becomes worn out as shown on the x-ray on the right. As the cartilage wears down, the joint becomes rougher and more friction occurs. This can cause pain and swelling. This can eventually result in total loss of cartilage and bone rubbing on bone. This can result in severe pain, swelling, deformity and loss of function and quality of life.

What are the symptoms?

Arthritis is a gradual condition. Patients often seek medical attention due to pain, swelling, stiffness and/or deformity. This is usually activity related. There may be symptoms of cracking/popping/locking and giving way. As the conditions worsens, the frequency and severity of pain increases. This can have a significant impact on function and quality of life.

Who gets ankle arthritis?
Anyone can get ankle arthritis. Osteoarthritis tends to become commoner as we get older. Ankle fractures, repeated sprains, and inflammatory arthritis (such as Rheumatoid arthritis) can cause arthritis to occur at a younger age.

What are the treatment options?

Not all cases of ankle arthritis need surgery. It is advisable to initially treat it without surgery, and leave surgery as a last resort. Some of the non-operative treatments include:

Painkillers – these can be topical or oral tablets. Ice packs can reduce swelling
Activity modification – avoiding activities that create excessive impact on the ankle joint and taking up activities with are less load bearing (eg. Cycling). Some working roles may need to be re-considered.
Footwear and orthotics – these include ankle braces, insoles and high top laced boots. A walking stick should be considered.
Weight loss - the ankle has to bear 5 to 7 times the body weight during day to day activities, such as standing and walking. Any amount of weight loss can reduce the load on the ankle joint and reduce pain.
Physiotherapy and hydrotherapy – can help with stiffness and discomfort and keep the surrounding muscle in good condition

What are the benefits of surgery?

In cases of severe chronic pain and significant decrease in function which is not responding well to non-surgical methods, then surgery may be a last resort to improve pain and function. The aim of surgery is to relieve pain and improve function and quality of life. Deformity can also be improved if present. Swelling, unfortunately, is usually permanent although may reduce to a degree after surgery.

There are different types of surgery undertaken for ankle arthritis. These are broadly categorised into fusion (arthrodesis) surgery or ankle replacement surgery.

Total ankle replacement (TAR)

A total ankle replacement is an operation that replaces the worn out ankle joint surfaces with metal components and a plastic bearing in between to allow motion. The metal components are fixed into the bone with pegs or screws and have special coating for the bone to grow into.

There is still ongoing research into who would benefit most from an ankle replacement. It is generally accepted that a total ankle replacement would not be suitable if:

You are young (usually under 55) or very active.
You have a severe foot deformity.
Your ankle is very unstable.
You have muscle weakness or a neurological disease
The bone under the ankle (the talus) has collapsed.

Approximately 80-90% of ankle replacements will still be in place 10 years after surgery, while some ankle replacements will loosen early (within 1-2 years) and require surgery sooner rather than later. Current registry data in the UK show that at 5 years over 90% are still doing well.

The decision to go for either a fusion or replacement requires a discussion with you and your surgeon. On some occasions, there may be no ‘correct’ answer and is therefore a matter of personal preference after discussion with your surgeon.

Summary of surgery.

The surgery is usually performed under general anaesthetic. Local anaesthetic is used to numb the nerves to the ankle and foot. You will generally require a few nights in hospital after the surgery.

A surgical incision is made at the front of the ankle. The worn out ankle joint is removed and the ankle replacement components are fixed to the bones via pegs with special coating to allow bone to grow onto the implant.

If necessary, further procedures may be undertaken to correct the ankle joint and keep it aligned. This will be discussed with you if necessary.

What are the risks with surgery?

The general risks with surgery include:

Bleeding – rarely may there be bleeding with results in a collection of blood under the wound. Bruising is common after this procedure
Swelling –Elevation is key to reducing this. However some residual swelling is often permanent after major surgery.
Stiffness – There will be stiffness in the ankle joint due to the nature of the procedure. An ankle replacement does not restore normal ankle movement and there may be a limp.
Infection – the risk is around 1-2%. Superficial infections can be treated with antibiotics. Deeper infections which are much rarer may require further surgery
Nerve damage – This can result in numbness over the scar but is generally not a problem. Occasionally a scar may be sensitive. Most settle down, but very few may require further treatment. Very rarely can a nerve injury affect the muscle in the foot
Clots in leg/lung – your risk of clots will be assessed prior to surgery and appropriate treatment/advice will be given.
Wound healing problems – this can result in infection and potentially plastic surgery. Elevation is key in the first two weeks to minimize swelling and help the wound heal. Smoking predisposes to this problem and will usually preclude surgery even being carried out.

The specific risks to this surgery include

Deformity – there may be some residual deformity if it was initially very severe. This may or may not require further surgery
Bones not healing (non-union / delayed union) – Sometimes the bones can take longer than expected to heal (up to 6-8 months). Approximately 10% of fusions do not heal. This usually does not cause any major problems, but rarely further surgery may be required.
Metal prominence – Sometimes the metalwork can be prominent under the skin. This can be removed at a later date, usually after a year.
Metatarsalgia – Sometimes other parts of the foot may undergo undue pressure when walking. This is often treated with insoles.
Fracture – If the bone fractures, this will be fixed immediately.
Arthritis in other joints – the surrounding joints are exposed to higher stress. This may result in arthritis in these joints after many years but many patients do not usually require treatment for this.
Damage to blood vessels – rare with this sort of surgery and great care is always taken to prevent this. One consequence includes amputation but this is incredibly rare as per below

Dislocation – this is rare with an ankle replacement.
Wearing out of the components - this occurs over several years, and is the usual cause of failure after 10 years or more. It can be treated by either replacement of the plastic bearing, or total revision of the replacement, or fusion surgery
Loosening of components – the replacement may loosen over time, necessitating further surgery either in the form of a revision ankle replacement or fusion
Continuing pain - up to 10% of patients with ankle replacement, there remains some pain in the ankle, which is not easily explained, as the X-rays look fine. Although in most cases these symptoms disappear after 12-18 months, a small proportion continue to have pain and require either reoperation or revision surgery.
Cysts – in some cases cysts may form or enlarge. Most of the time this may simply be monitored. In some cases, further surgery may be required.
Chronic regional pain – This is excessive pain after surgery and is a very rare complication.
Amputation – this is extremely rare. However deep infections, vessel injury or chronic pain may necessitate amputation.

After your ankle surgery

After surgery, the limb will be immobilized in a partial below knee cast. This will be changed to a full below knee cast at a later stage (usually 2 weeks after surgery).

You will have to wear the cast for at least 6 weeks, and this is followed by a period in a walking boot for a further 6 weeks. You will need crutches or a frame to help you mobilise during this period.

Patients are non-weightbearing immediately after surgery. Depending on your situation, your surgeon will allow you to put weight on your ankle after about 2 to 3 weeks. You should discuss your post-operative care with your surgeon.

Because you are immobilised after surgery, it is usually recommended that you have blood-thinning medication to prevent blood clots whilst in the cast. This usually involves a daily self-administered injection which will be explained while you are in hospital.

After the plaster cast is removed, you will require a walking boot for a few more weeks. You can then transition to wear your normal shoes. Often foot wear changes may be necessary after surgery (wider/larger shoes).

Advice after surgery

The foot should be strictly elevated for the first 2 weeks to avoid excessive swelling which could compromise the wound. Aim to keep the foot elevated for 55 minutes of every hour

The cast dressings should not be disturbed unless there is a concern with the wound. At around 2 weeks after surgery, you will return to the clinic to have the cast and stitches removed. A new full cast will be applied at this time.

You must keep the cast and leg dry and clean during the time the cast is on.

Your surgeon will inform you of when you are allowed to bear weight in cast. You will need crutches or a frame. The physiotherapist will show you how to use them.

It may take several months before you can drive. Please check with your insurer.

Going back to work depends on the activity undertaken at work and should be discussed with your surgeon.

Most patients go back to recreational walking and light activities (such as cycling and golf). Although more vigorous activities such as squash, tennis or football may be possible, we do not recommend them as they put a lot of stress across the other joints, which will eventually wear and become painful. This can also result in early loosening of an ankle replacement. Similarly, walking or hiking on rough and uneven ground is possible but will put more stress on the adjacent joints or implant. You can protect the adjacent joints by wearing a sturdy above-ankle walking boot. Swelling is often permanent following major surgery and a full recovery can take up to 18 months. This is a normal recovery. Often a full recovery takes much longer than one would expect.

If I have any questions or concerns?

These guidelines are to help you understand your operation. This level of detail may cause concern, anxiety, or uncertainty. Please let your doctor or nurse know so that we may address these issues.

We aim to see you back in the clinic at regular intervals to monitor your progress and answer any questions you may have during your recovery.

If there is concern regarding the wound, such as increased redness, pus, discharge, or pain, then seek medical attention either at your GP or nearest Emergency department.

Above all else, please do not proceed with surgery unless you are satisfied and understand all you want to know about the operation.