Total ankle replacement: who it suits, risks and recovery in the UK

The ankle joint is a hinge formed by the lower end of the shin bone (tibia) and the talus. A Sussex NHS patient guide explains that a total ankle replacement involves taking out the worn-out ends of these bones and replacing them with artificial ends made from metal with a plastic insert, called a prosthesis. A Dudley NHS guide describes two metallic parts with a plastic insert between them that allows the joint to glide and rotate.

The aim, according to the Dudley guide, is to relieve pain whilst preserving the ankle’s range of movement. The Sussex guide adds that unlike an ankle fusion, a replacement allows you to move your joint after surgery, that in most cases a replaced ankle will have the same range of movement as before surgery, and that there may be less strain on neighbouring joints.

An NHS orthopaedic hospital guide lists the surgical treatments for ankle arthritis: arthroscopy, debridement to remove bone spurs, ankle fusion and total ankle replacement. It says there are many ways to treat arthritis before surgery, including physiotherapy, injections and therapeutic shoes or insoles, and that the decision to have surgery is based on how much everyday activities are limited by pain.

It says a replacement will usually be advised for people who, due to age or health, will be somewhat restricted in the level of physical activity after surgery, and that fusion is preferable for active patients whose only limitation is the painful ankle, and for ankles that have become virtually immobile or severely tilted. The Dudley guide says the choice is a shared decision considering deformity, movement, general health, age, physical demands, soft tissues, previous fractures and BMI.

The orthopaedic hospital guide says a cut is made over the front of the ankle, the damaged joint surfaces are cleared away and shaped if needed, and metal surfaces with a plastic insert are used as the new joint. Sometimes additional surgery is needed to correct the alignment of the foot. It usually takes about one and a half hours under a general anaesthetic, with a lower leg nerve block for pain relief. The Dudley guide gives about 2 to 3 hours and says a thigh tourniquet is routinely used.

The Sussex guide says that unless told otherwise you normally stay in hospital overnight, and that some people go home the same day, while the Dudley guide says 2 to 3 days. Before surgery a pre-admission nurse checks that you are well enough, and an occupational therapist or physiotherapist may help plan how you will manage at home, including stairs.

The figures vary between hospitals, so they should be treated as approximate. The Sussex guide describes infection (deep infection rare, less than 1%), wound healing problems, loosening, ankle fracture (about 1 in 25), blood clots, persisting pain and stiffness, nerve damage and, rarely, amputation (about 1%). It says the risk of needing a revision total ankle replacement is 15% at 10 years.

The Dudley guide lists infection or wound problems (3%), blood clots (1%), fractures (5%), chronic pain syndrome or unexplained pain (10%) and need for revision surgery (3 to 5% at 5 years). The orthopaedic hospital says that in up to 10% of patients some ankle pain remains that is not easily explained, and that about 1.5 to 2% fail or wear out each year, meaning a 1 in 5 chance of failure by 10 years.

The Sussex guide notes that if an ankle replacement fails it is often treated by ankle fusion, usually with a bone graft, which is more complex and carries higher risks than a primary fusion.

The orthopaedic hospital guide says you return to the ward in a non-weight-bearing back-slab cast from toe to knee, should keep your leg up for at least 55 minutes in every hour for the first 2 weeks to reduce swelling, and will not be allowed to put weight on the leg for two weeks. The back-slab is then removed and a lightweight cast applied, after which you are usually allowed to put weight through the ankle. You are reviewed at 2 weeks and 6 weeks.

Milestones from the same guide: return to desk work from about 4 weeks if the leg can stay raised; walking independently by about 3 months; normal footwear by about 3 months though swelling can take several months to settle; driving from about 4 weeks for a left ankle in an automatic car and otherwise about 3 months; and low-impact sport at about 6 months. The Dudley guide describes progression to full weight bearing by 6 to 8 weeks and improvement over a twelve-month period. People are advised to expect to be told the details by their own team.

The Sussex guide says research shows that if patients follow recovery instructions about 90% feel less pain, move more easily and enjoy a better quality of life, and that 85 to 90% of ankle replacements still work well 10 years after the operation. The Dudley guide says satisfaction rates are around 80% and that short- to medium-term results are very good but long-term results are not known.

The orthopaedic hospital describes expected outcomes as improved function and pain relief, increased walking tolerance, possible return to no-impact or low-impact sport but strenuous sport being unlikely, and range of movement maintained but not likely to improve significantly. It says patients undergoing ankle replacement are contacted yearly for review. NHS surgery is free at the point of use.