Pain and stiffness caused by arthritis of the ankle may lead patients to consider joint replacement surgery if conservative (non-surgical) treatment methods are not successful. Unfortunately, some patients go on to experience problems with their ankle replacement following surgery and may require revision procedures. In this informative article, esteemed consultant orthopaedic surgeon Mr Andrew Goldberg, who specialises in treatment of the foot and ankle, expertly explains when revision surgery is needed following ankle replacement. This in-depth guide, the second in this series on ankle replacement, also details the rare complications associated with ankle replacement.
Are ankle replacement procedures similar to those of the knee?
The technology behind ankle replacements is the same as knee replacement. Ankle replacements provide excellent pain relief and good function but, like all joint replacements, they are prone to wear and failure with time. This appears more likely to occur in ankle replacement than in hip or knee replacements. The reasons for this include the fact that the ankle is smaller and the joint is under more load and torque than any other lower limb joint. In addition, ankle replacements are less commonly performed and the average surgeon only performs 4 ankle replacements per year. It is well known that surgeons who perform a higher number of joint replacements achieve better results.
Is revision surgery often required following an ankle replacement?
The need for the implant to be later removed (which is revision surgery) is approximately 1.5% per year, meaning that after ten years, about eighty-five per cent of ankle replacements are still working well.
Some ankle replacements will loosen and may then cause pain and a further operation will be required. Many of these failures are identified early on, usually by the one year X-ray. Those patients who don’t experience problems during the first year are more likely to continue to have their ankle replacement last with no issues going forward.
Ankle replacements usually fail because of a loosening of the metal components implanted during surgery. Additionally, cysts can form in the area over time caused by wear of the plastic component. Should the ankle prosthesis wear out, loosen or fail in any way, revision surgery may involve another ankle replacement or the ankle replacement can be removed and an ankle arthrodesis performed, where the bones of the ankle are fused together.
What are the potential complications of ankle replacement surgery?
As with all types of surgery, ankle replacement surgery carries some risks and can cause pre-existing conditions to worsen. These risks occur rarely (in up to five in every one hundred surgeries) and commonly include:
- post-operative pain, which can be managed with local anaesthetic, administered by a surgeon or anaesthetist, and simple pain killers
- swelling in the ankles and feet, caused by the effects of gravity which can last from several months up to a year
- scarring, which in rare cases may be painful and inflamed
Redness or inflammation at the site of the surgical wound is also a possible complication of ankle replacement surgery. This occurs as the skin’s blood supply at the front of the ankle is not as effective as it is in other areas of the body and therefore, wound healing issues including redness, bruising and blistering can sometimes occur. 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.
Additionally, minor wound infection can lead to redness in the area and in some cases, the edges of the wound do not heal completely. Antibiotics may be required to resolve this. People with diabetes, those who smoke and people who take immune suppression medication such as steroids or rheumatoid medication generally run an elevated risk of developing these types of complications following surgery.
Numbness and nerve injury is also a possible complication following surgery. Numbness or tingling at the surgical site is common and is usually temporary, but up to fifty per cent 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, which occurs in less than three per cent of cases, 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 (found 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 sole of the foot or the space between the big and second toes.
The “fight or flight” nerves to the ankle and foot can stop working as they should which can lead to swelling, stiffness and pain as well as changes in colour and temperatures in the foot. This is known as complex regional pain syndrome (CRPS) and is rare but can occur in up to two per cent of surgeries. In very rare cases, this can be permanent, but can usually be resolved over several months with counselling and physiotherapy.
If the area is immobilised following surgery, it is likely that some stiffness will develop in the joint. Physiotherapy may be necessary to improve the range of movement of the foot and ankle.
Deep vein thrombosis (DVT) due to a blood clot in the calf, is not uncommon and may occur in five per cent of cases because the limb is immobilised after the surgery. Blood-thinning medication can help to reduce the risk, along with a special compression stocking which promotes improved venous circulation.
Less commonly, complications such as pulmonary embolism may occur in less than 0.5% of cases. In such cases, a blood clot can spread up from your calf (DVT) into your lungs which can cause chest pain or shortness of breath. This is a serious complication and may require a prolonged stay in hospital and long-term blood thinning medication. If this unfortunate complication arose, symptoms such as weakness and shortness of breath may also last for several months.
Although extremely rare in ankle replacement surgery, anaesthetic complications can occur, including death. This is very unusual but sometimes occurs when the patient suffers from other pre-existing conditions.
These complications only occur very rarely but nonetheless, it is important to have a good understanding of any possible risks of a surgical procedure before undergoing it. Your surgeon can discuss any particular concerns you may have about your individual case before surgery.
Mr Goldberg is one of the UK’s leading consultant orthopaedic surgeons who specialises in treatment of the foot and ankle. You can learn more about Mr Goldberg or schedule a consultation by visiting his Top Doctors profile.