Which patients get the most benefit from ankle replacement surgery? New research aims to find out
Published on 14 April 2014
Ankle arthritis is a painful condition that affects quality of life as much as severe hip arthritis or heart failure. Ankle replacement surgery is now available, and although numbers are small in comparison to hip and knee replacement, they are rising slowly.
Of the 30,000 cases of ankle osteoarthritis seen by hospital specialists every year in the UK, only about 1,200 of them will undergo ankle replacement surgery.
This is partly due to the fact that fusion surgery – in which the ankle joints are screwed together – is much more commonly performed.
There are two distinct types of patient who require surgery on their ankle – those who have injured or damaged the joint through sport in their youth and developed osteoarthritis in their middle years as a result, and older people whose cartilage has slowly degenerated as they have aged.
This first group is much bigger, but specialists tend to recommend ankle fusion due to their young age. Ankle replacement, on the other hand, tends to be reserved for the older, less mobile group, and is carried out on people with an average age of 64. This type of surgery results in more movement and flexibility in the ankle than fusion but, because of the uncertainty of the long-term outcome, tends to be reserved for those who are less active.
Back in the 1970s the situation was similar for hip arthritis, when fusion of the hip was a reasonable alternative for young patients. Nowadays, however, no surgeon would recommend fusion of a hip over hip replacement, and it might be that in the future, as more evidence emerges on the long-term outcome, the same will happen with ankle replacement.
“If you’re under 60 in the UK with ankle arthritis, you’re more likely to have your ankle fused,” explained Andy Goldberg, consultant orthopaedic surgeon at the Royal National Orthopaedic Hospital in Stanmore.
“There are pros and cons to both fusion and replacement surgery. With fusion there’s a risk that patients will develop wear and tear in adjacent joints, and subtle differences in their gait – they will limp when they run, for example.
With ankle joint replacement there’s a failure rate of up to 19% after 10 years – much higher than for knee and hip, and there is an element of uncertainty about the long-term results. It may need to be revised either to another ankle replacement or even fusion down the line.”
Ankle replacement surgery remains a very specialist form of surgery and as yet information on how well these operations perform is currently lacking. Also, the views of patients on the outcome of their surgery have not been measured in a consistent or reliable way.
Researchers have now been awarded funding of £220,000 by Arthritis Research UK to do just that. A team led by Professor Alex MacGregor from the University of East Anglia will use the three-year grant to investigate how well the implants perform in individual patients after one year. They will also assess the health economic impact of the procedure. The study will run alongside a NHS-funded clinical trial, led by Mr Goldberg, comparing fusion and replacement surgery.
By using a newly developed questionnaire called a patient-reported outcome measure, or PROM, on 600 people, seeking their views on the success of their operation, the research team will be able to work out who is best suited to undergo this type of surgery.
Professor MacGregor will also use the National Joint Registry to collect data on patients undergoing ankle replacement surgery.
“Detailed clinical and radiological data will allow us to analyse how factors such as pre-operative disease severity, surgical technique and treatment after surgery affect the total outcome,” explains Professor MacGregor. “We’ll also undertake a health economic analysis to estimate the cost-effectiveness of the procedure when compared to not having surgery or having an ankle fusion.
“Our analysis will enable us to have a greater understanding of who might benefit most from this type of treatment for severe ankle disease.”
Adds Mr Goldberg: “Currently we tell patients what the literature says about ankle replacements, but what really matters is the views of patients who’ve had it done. It’s really important that we can start giving meaningful information about outcomes of this type of surgery to patients, and that’s the purpose of this study.”
Arthritis Research UK’s booklet ‘Foot and ankle surgery for arthritis’ is available on 0800 389 6692 and firstname.lastname@example.org.