All surgery carries risk and it is really important before you undergo any surgery that you have considered what are the risks of ankle replacement as well as the alternative options open to you.
What is the alternative to ankle replacement?
Most patients with ankle arthritis respond to non-surgical treatments and surgery should usually only be considered on failure of non-surgical treatments such as physiotherapy or physical therapy, ankle braces or ankle supports, activity modification, and analgesia. If these treatments have been tried and failed then surgery can be considered and hence the need to understand the risks of ankle replacement.
What are the risks with ankle replacement?
All operations have risks and any underlying medical conditions that you suffer may worsen due to the surgery. Here are the common risks of ankle replacement.
COMMON RISKS (occur in up to 5 in every one hundred surgeries)
- Pain – During most surgeries your surgeon or anaesthetist will use local anaesthetic to minimise the postoperative pain, but you should be prepared to have some pain or discomfort, which usually responds to simple analgesia.
- Swelling – Due to the effects of gravity, ankles and feet tend to swell, and this can sometimes last several months. After an ankle replacement it can take 6 months or even up to a year to obtain the final result.
- Scarring – any type of surgery will leave a scar, occasionally this will be painful and inflamed.
- Wound redness or inflammation – the blood supply to the skin at the front of the ankle is not as good as other areas of the body and so it is not uncommon to get some wound healing issues, such as redness, bruising and blistering. In most cases this settles by 3-4 weeks but if you have poor circulation to your foot then it can take longer for the wound to heal. There is also the risk of minor wound infection, and some minor redness of the wound can occur because of this and in some cases the wound edges do not heal fully. In some cases you may require antibiotics to get this to settle. Risks are higher in diabetics, those on immune suppression medication (eg steroids or rheumatoid medication) and smokers.
- Numbness & Nerve Injury – Numbness or tingling at the surgical site is common and is usually temporary, but up to 50% of patients who have an ankle replacement will get some numbness on the top of their foot. This is not usually a problem. If a key nerve is injured (up to 1.5% of cases) then it can cause permanent numbness, tingling, and shooting pains requiring medication or further specialist input. The two key nerves at risk in an ankle replacement are the tibial nerve at the back of the inside of the ankle and the deep peroneal nerve at the front of the ankle. Injury to these nerves can lead to numbness to the toes.
- Complex regional pain syndrome – this is where the “fight or flight” nerves that supply the ankle and foot go on strike and can cause swelling, stiffness, pain, and colour and temperature changes to the foot. It is not common but can occur in up to 2% of surgeries. Treatment requires counselling and physiotherapy and it could take several months to improve and may (rarely) be permanent.
- Stiffness – after surgery, especially if the limb is immobilised you will usually suffer from stiffness that may require physiotherapy to try and improve mobility of all of the joints of the foot and ankle.
- Blood clots – deep vein thrombosis (DVT) due to a blood clot in the calf, is not uncommon and may occur in 5% of surgeries because after the surgery the limb is immobilised. Your surgeon will discuss blood-thinning medication to reduce the risk but even on the medication it can still occur. They may also put a special compression stocking on the other leg to improve venous circulation.
LESS COMMON RISKS (occur in up to 1 in every one hundred surgeries)
- Pulmonary Embolism – Less commonly (less than 0.5%) a blood clot can spread up from your calf (DVT) into your lungs and this is known as pulmonary embolism and cause chest pain or shortness of breath. This is a serious complication and may require a prolonged stay in hospital and prolonged blood thinning medication and it can lead to weakness and shortness of breath for several months.
- Deep infection – Although the operation is performed under sterile conditions and all precautions are taken to prevent this, it can happen, and if the wound does not settle on antibiotics, you may require a further operation which may even require the removal of the implant and sometimes complex and lengthy treatment.
- Fracture- Any surgery involving cuts to the bone risks fracturing (or breaking) a bone. This may require fixation by your surgeon at the time of the operation or if it occurred after the initial surgery, then you may require a second procedure to deal with this later. You may also have a change to your rehabilitation protocol. Ultimately, your surgeon will act in your best interests at the time of surgery to give you the best outcome.
- Prominent metalwork – if metalwork (screws or plates) are used in addition to the ankle replacement (for example to shift your heel or change the position of your fibula) then in some cases these can be prominent under the skin, requiring a second procedure to remove them at a later date.
- Poor bone integration into the implant – It is not common for the implant not to bed in to the bone but this can happen. The reasons are sometimes difficult to explain, and it can be due to a low grade infection or just micromotion between the implant and the bone. Smoking also can lead to poor local blood supply to the bone-implant interface. If this happens you may experience pain on walking and it may require the operation to be revised.
RARE RISKS (occur less than 1 in every one hundred surgeries)
- Blood vessel damage – damage to the blood supply could lead to bleeding and bruising after the surgery. In very rare cases this could effect the viability of the limb and require the involvement of a vascular surgeon and possibly even amputation.
- Further investigation or surgery- sometimes the results of the surgery will not meet your expectations, especially if complications arise, and may require further investigation or further surgery.
- Anaesthetic complications including death – whilst this is extremely rare in ankle replacement surgery, it can occur especially if there are pre-existing medical conditions.
NEED FOR RE-OPERATION OR REVISION
Research suggests that the need for minor surgery to an ankle replacement within the first year can be as high as 5%. This can be for any of the reasons highlighted above and it is important to be aware that ankle replacements are not yet as reliable as hip or knee replacements. The need for the implant to be removed and either replaced or the ankle converted to an ankle fusion is known as a revision operation. The risk of revision is about 1.5% per year, meaning that after 10 years about 85% of ankle replacements are still working. While some ankle replacements will loosen early (within 1-2 years) and require surgery sooner rather than later most ankles that last the first year go onto last without problem. The most common reason for an ankle replacement to fail is loosening of the metal components. This might be accompanied by cysts that have formed due to wear of the plastic component. If the ankle does wear out, becomes loose or “fails”, then revision can either be to another ankle replacement or conversion to an ankle arthrodesis (fusion). An arthrodesis following ankle replacement is usually successful but is a bigger operation than if it was done in the first place. In very rare circumstances (usually due to severe infection or blood flow issues, an amputation can be considered).
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