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Treatments for ankle arthritis including ankle replacement

Posted Feb 09 2012 8:45am

This article by an expert in total ankle replacement discusses the latest treatment options for ankle arthritisInflammation of one or more joints of the body., an increasingly common condition. This will be of interest to anyone who suffers from pain in their ankle and would like further advice on what the suggested causes and treatments might be.

The ankle is the most commonly injured joint in the body. This is related to increasing participation in sport, as well as people leading a generally more active lifestyle. Accordingly we are seeing more ankle fractures and sprains presenting to our Accident and Emergency departments. Whilst the majority of these injuries heal uneventfully, a small proportion of patients will go on to develop ‘wear and tear’ or ankle arthritis. Although not as common as hip and knee arthritis, ankle arthritis has steadily become more common, and the upward trend is still continuing.

When established, studies have shown that the symptoms of end-stage ankle arthritis have the same effect on quality of life as end-stage hip arthritis, and therefore should assume equal importance and priority.

This article covers the causes of ankle arthritis, with a focus on the treatment options available, including the role for Total Ankle Replacement (TAR).

Only a minority of people who sustain an ankle injury go on to develop ankle arthritis. Whilst it does depend on the nature of the injury and how it is treated, ankle arthritis tends to develop many years later. More common reasons for on-going pain soon after an ankle injury include overgrowth of the capsule of the joint (synovitisInflammation of the membrane that lines a joint capsule.) which can impinge, isolated damage to the joint surface such as an osteochondral defect (hole in the joint lining), or damage to the many tendons that cross the ankle joint. An x-ray will identify arthritis if present. More sensitive tests such as an MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. or CTThe abbreviation for computed tomography, a scan that generates a series of cross-sectional x-ray images scan will often be organised to gain further information.

Ankle arthritis itself refers to the loss of joint cartilage (gristle) that covers the tibiaThe shin bone. and talus bones which constitute the ankle joint. Figure 1 shows an arthritic joint demonstrating loss of joint space and osteophytes (bony overgrowth).

x-ray image of an arthritic ankle

The most common type of ankle arthritis is ‘wear and tear’ or osteoarthritisA disease mainly of the large joints of the body, as a result of wear and tear of the surface cartilage.. The following list summarises the important causes:

1. Trauma: Ankle fractures and recurrent ankle sprains are by far the most common reasons for developing ankle arthritis. Other less common injuries implicated in arthritis include tibial ‘pilon’ fractures and talus fractures.

2. Abnormal joint loading: If a fracture of the tibia does not heal in perfect alignment, this could place abnormal forces and stresses across the ankle joint, leading to arthritis. Equally, a flat or high-arched foot commonly transfers stresses to the ankle joint, leading to premature wear and tear.

3. Infection: Joint infectionInvasion by organisms that may be harmful, for example bacteria or parasites. (septic arthritisInflammation of a joint due to a bacterial infection.) is a devastating complicationA condition that is linked to, or is a consequence of, another disease or procedure., which if not treated promptly, will often progress rapidly to arthritis.

4. Inflammatory conditions: Includes rheumatoid arthritisA type of autoimmune arthritis featuring chronic inflammation of the small joints, especially in the hands and feet, and eventually leading to joint destruction and deformity which commonly affects the ankle joint. With improvements in anti-rheumatoid medications, however, fewer patients are requiring surgical intervention.

5. Primary arthritis: This is the most common cause of hip and knee arthritis, and it has a significant geneticRelating to the genes, the basic units of genetic material. element. Essentially, it is wear and tear that develops without an injury, or obvious cause. The ankle joint is much less commonly affected by primary arthritis.

6. Other causes include goutA common metabolic disorder that causes attacks of arthritis, usually in a single joint. Gout is due to high levels of uric acid in the blood. (also called crystal arthritis), haemophiliaA hereditary disorder that causes very slow clotting of the blood, due to deficiency of a coagulation factor (either Factor VIII or Factor IX). (recurrent bleeds into the joint) and diabetesA disorder caused by insufficient or absent production of the hormone insulin by the pancreas, or because the tissues are resistant to the effects. which can result in damage to the nervesBundles of fibres that carry information in the form of electrical impulses. that supply the ankle joint. This produces a problem called a Charcot ankle, and the lack of sensation allows the injury to go unrecognised, resulting in severe ankle arthritis and deformity.

A combination of pain, stiffness and swelling are the most common symptoms. Pain is often felt deep within the ankle, although bony spurs (osteophytes) typically form at the front of the joint and can cause catching or impingement. Start-up pain i.e. pain felt first thing in the morning is common. Walking long distances, hill walking, and negotiating stairs can become increasingly difficult as the arthritis progresses. Eventually pain may be felt at rest and at night. You may notice a limp, which is commonly associated with pain, but can be related to a reduction in the amount of movement within the joint.

Ankle arthritis can often be treated without surgery, especially in the early phase. In a proportion of patients, this may be all that is required. General measures include weight loss, activity modification and, if allowed, anti-inflammatoryAny drug that suppresses inflammation medication. Your GP will be able to advise you about painkillers, although the long-term use of any medication should be monitored carefully. Physiotherapy can be helpful in the early phase, concentrating on strengthening the muscles that control the ankle joint; although pain is often a limiting factor. Orthotic devices and footwear modification should be tried. If you have an obvious flat or high arched foot, this can be supported and sometimes corrected with an insole that will take the pressure of the ankle joint. A rocker (curve) to the sole of a shoe can be adapted to reduce the work your ankle joint needs to do during walking. After an initial consultation with a Consultant Orthopaedic Foot and Ankle Surgeon, you will often be referred to a physiotherapistA healh professional who specialises in physical therapies, such as exercise, massage and manipulation., orthotist or podiatristAnother term for chiropodist, a healthcare professional (not medically qualified doctor) specialising in foot care. for a trial of conservative treatment.

Local anaestheticA medication that reduces sensation. and steroid injections can help reduce the inflammationThe body’s response to injury. associated with the ankle arthritis, and are often successful for short periods of time, usually one – two months. The drawbacks include the need to repeat them regularly and the small possibility of introducing infection which can compromise future treatment.

Other injections are available on the market, under the umbrella of ‘viscosupplementation’. This involves injecting hyaluronic acid, available under a number of commercial names, into the joint. Hyaluronic acid is a naturally occurring substance that lubricates and cushions the joint. The wear and tear process reduces the levels of this substance, and therefore replacing it has been suggested as a measure to reduce pain associated with arthritis. National guidelines have been published with respect to the knee joint, and it is currently not considered a cost effective treatment. A few studies have been conducted looking at its effectiveness in ankle arthritis and it has been shown to be a safe treatment with a potential to improve symptoms for up to six months and sometimes longer. Higher quality studies are required however before we can recommend widespread use and justify its significant cost. For the momentIn physics it is the tendency of a force to twist or rotate another object in the UK, this is not a common treatment used in the management of ankle arthritis.

There are a number of options available, and you should sit down with your Consultant Orthopaedic Foot and Ankle Surgeon and make an individualised treatment plan.

The surgical options offered to you will depend on a number of factors:

1. Your age
2. The extent of your arthritis and the degree of deformity (tilting of the joint)
3. The quality and strength of your bone
4. Your job and current level of activity
5. Your surgeon and his/her philosophy/training

The important decision you will need to make with your surgeon, is whether you are a candidate for arthroscopic debridement, a fusion or a replacement. These options are discussed below:

This involves two small 1cm incisions over the front of the ankle. A camera (arthroscope) is used to inspect the ankle joint and specialised instruments are used to clear any bony overgrowth or unstable areas. The most benefit can be gained when there is confirmed bony overgrowth and your symptoms are directly related to catching/impingment at the front of the ankle, particularly when your foot is pulled upwards. Symptoms often improve but there is no degree of predictability, and often arthroscopic debridement is used to delay the need for a more permanent solution.

An ankle fusion is recognised as the gold standard treatment for symptomatic ankle arthritis. The principal of a fusion is to ‘glue’ the ankle joint together so that no movement occurs and therefore pain is eliminated. The joints surrounding the ankle are then required to compensate and often significant stresses are placed upon them. Despite this, the early results of an ankle fusion are very good, and patients often return to a very high level of function. The technique involves exposing the joint through a 10cm incision over the front or side of the ankle. The remaining cartilage is removed and the joint surfaces are taken back until signs of bleeding are detected. The surfaces are then squeezed together with the ankle joint held 90 degrees to the floor, and usually screws are used to secure this position. A plaster cast is used for six weeks in total, and no weight-bearing is allowed during this time. If x-rays are showing signs of healing at this point, weight-bearing is started in an Aircast boot. It generally takes 9-12 months to fully rehabilitate following an ankle fusion.

Complications can occur although they are fortunately quite rare. In one in twenty cases, the fusion does not work, either due to a technical error, poor bone quality, using medications that prolong healing, or as a result of smoking. If this occurs, a repeat operation is required to restabilise the joint and bone grafts are often used. If smoking was the cause, this should be stopped prior to any repeat operation.

Occasionally the foot is placed in a suboptimal position. This can result in ongoing pain, as abnormal stresses will be placed through the foot and orthoticsThe fitting of an appliance designed to support joints or correct deformity, known as an orthosis. (insoles) are often required to salvage this problem. In the long-term, stress placed on the surrounding joints leads to wear and tear and arthritis, which may then require further fusion of these joints. The skin around the ankle is thin and the bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. supply is not as generous as elsewhere in the body, and so is proneLying face-downwards. to delayed healing. This generally settles with simple wound care management. Rarely, the wound breaks down requiring input of a plastic surgeon.

Given the potential wound healing problems associated with open ankle fusion, a new approach was developed, performing the fusion with the help of a camera – arthroscopic fusion. The same two 1cm incisions (as described above) are utilised and specialised instruments are used to clean the joint and produce bleeding surfaces. The same method of stabilisation is used as in an open fusion, and the only difference is the size of the wounds. Clearly this has immediate benefits for you. In open fusions, serious wound problems are rare yet can be devastating when they occur.

Not everyone is suitable for this minimally invasive approach. If there is significant tilting of the ankle, the surgery becomes more difficult to perform and often one reverts to the open technique. As our experience has grown we are now able to correct larger deformities, but ultimately the goal is to achieve a solid bony fusion at the first attempt and the technique chosen should reflect this. Studies have shown that both open and arthroscopic surgery produce reliable fusion rates, however wound healing problems are much less with the arthroscopic technique. This method is now routine practice for Consultant Orthopaedic Foot and Ankle Surgeons, and you should ask your surgeon if you are suitable.

x-ray image of total ankle replacement

Preservation of movement is something that we all prefer. It is human nature to want to keep movement, as this represents normality. Total ankle replacement (TAR) is an option and has seen resurgence in recent years. The initial designs introduced in the 1970’s, were not compatible with the complexity of the ankle joint and they failed quickly. TAR was therefore not considered a viableCapable of survival. option, until more recently when prosthesisAn artificial device attached to the body. design and instrumentation was improved and Orthopaedic Surgeons were trained specifically in Foot and Ankle Surgery. Figure 2 shows a typical ankle replacement.

Not everyone is suitable, and patients with more than 10 degrees tilting of the joint, are at risk of early failure of a TAR. Other factors I consider include your age, occupation, weight and bone quality. If you are involved with heavy labour, a fusion may be a better option. TARs tend to preserve and occasionally improve your range of movement, and so a fusion can be a better option if you have a very stiff ankle to start with.

Clear benefits of a TAR, include preservation of movement, and gait studies have shown that patients have a more symmetrical walking pattern compared to those with a fusion. Although not yet proven, the preserved movement is thought to protect the surrounding joints from ‘wear and tear’, or at least slow down the process. This can potentially avoid the need for further surgery.

The surgery is performed through a 10-15cm incision made over the front of the ankle. The joint surfaces are cut to allow the prosthesis to be inserted. The tibia and talus are resurfaced with a metal prosthesis usually made of cobolt chrome, and a plastic liner sits between the two metal components. Wound healing problems can occur and are minimised by careful handling of the skin during surgery. Infection can be serious if it penetrates into the joint. Fortunately this is rare (less than 1%) as it would require removal of the whole TAR, putting in a spacer for six weeks, with intravenousWithin a vein. antibioticsMedication to treat infections caused by microbes (organisms that can't be seen with the naked eye), such as bacteria. and a further TAR or fusion when the infection settles. Like all prostheticArtificial. joints, they have a limited lifespan, and can loosen. If this happens, a further TAR can be performed if there has not been too much bone softening. If the bone has been eroded, a fusion is required which can be challenging as a large hole needs to be filled, and often allograft bone (from another person) is required to bridge the gap.

Many different prostheses are available on the market, and currently there are no long-term studies from independent surgeons (those not involved with prosthesis design). In the hip, we can quote 99% 15-year survival, in the knee 95%, and this reflects the more complex biomechanics. Similarly in the ankle the complexity of the joint, together with the small surface area of contact (resulting in higher stresses), means that the few long-term studies available quote 80% 10-year survival. Therefore it is very important that you make a careful informed decision with your surgeon about the best option for you.

You should sit down with a Consultant Orthopaedic Foot and Ankle Surgeon, and make a treatment plan.

The following is my personal philosophy on the treatment of ankle arthritis. The figures and ages quoted are not absolute and simply allow me to distinguish groups of patients from others. Ultimately the decision on treatment is based on a full discussion of the benefits and drawbacks of each option.

In simple terms, after trying the conservative measures discussed above, the important decision that you need to make with me is whether you should have a fusion or a replacement.

If you are under 50 years of age, I generally do not recommend TAR, as the prosthesis will certainly fail in your lifetime and you would be committing to multiple operations, each becoming more difficult as time passes. I would offer you a fusion, either arthroscopic or open, based on the degree of tilting and the quality of your skin. There are always exceptions to the rule and a patient under 50 with rheumatoid arthritis, who presents with ankle arthritis, and has had an ankle fusion on the other side, can become a candidate for a TAR, as it can be very difficult to walk with both ankles fused.

If you are over 65, and have good bone stock and minimal ankle tilting, I consider TAR to be a good option for you. You are likely to be less demanding on it, and as the years pass, place less stress through it and therefore prolong its lifespan. You would benefit from the potential preserved movement, which will give you better function and potentially protect the surrounding joints from arthritis. Whilst this hasn’t been formally proven, it would seem logical that less stress placed on these joints would offer protection.

If you are between 50 and 65, this is a grey area and I would discuss the options with you. I do not rely on absolute ages and each individual is unique, and so a TAR can still be a good option for you. I monitor the progress of all my patients with scoring systems before and after surgery, and I request follow-up with you on a yearly basis. We are now submitting data to the National Joint Registry, similar to hip and knee replacements, and we currently await the early results from this exciting venture.

Ankle arthritis is an increasingly common problem for which there are many solutions. You should seek the help of a Consultant Orthopaedic Foot and Ankle Surgeon, who will be able to discuss the options with you. If simple measures fail, surgery generally consists of a fusion or a replacement. The best option for you is based on many different factors, and ultimately should be safely performed and improve your quality of life.
 

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