No pain, no gain
Published on 16 July 2013
Knee replacement surgery can reduce pain and improve quality of life – but not for everyone. Jane Tadman reports on how intensive post-operative physiotherapy could play an important part in ensuring a better success rate.
Knee replacement surgery can be a transformative experience for many thousands of people suffering from crippling, painful osteoarthritis.
Around 75,000 people in the UK have their knees replaced every year – more than have a hip replacement. Although a replacement knee can never be as good as the original, in the majority of cases it eradicates much of the pain, and leads to a welcome increase in mobility.
However, recent reports indicate that as many as 20% of these people are not fully satisfied with their knee replacements one year after surgery.
“Sadly, a colossal 15,000 patients every year are not fully satisfied a year after their operation, so there’s a great need to identify these patients and determine if anything can be done to improve their outcome,” explains Professor Hamish Simpson, professor of orthopaedics and trauma at the University of Edinburgh and an orthopaedic surgeon at Edinburgh Royal Infirmary.
New research carried out by an Arthritis Research UK-funded orthopaedic team at the University of Oxford looking at the success rate of the operation in younger people, has also revealed that although increasing numbers of people under the age of 55 are having knee replacement surgery, they are less satisfied with the outcome of their operation than older patients aged 65 to 85 – even though they gain greater improvement.
“Clearly expectations are higher in younger people: they expect that they will have a completely normal knee after the operation and be able to do all the sports and activities they did prior to surgery, and that’s not always the case,” says lead researcher David Beard, professor of musculoskeletal science at the Nuffield Orthopaedic Centre, who worked on the study with colleague Derfel Williams. “Older people tend to be are less active, and hence are happier with the outcome.
“Twenty years ago people having knee replacements were aged over 70, but that profile has now changed, with much younger people saying they would have the surgery now and would have an improved quality of life, and worry about the future later.”
This lack of satisfaction from knee replacements is obviously of much concern to patients themselves, as well as researchers and clinicians. While some of that dissatisfaction is undoubtedly due to unrealistic expectations, some of it is due to the fact that many people are still in pain after the operation.
(There is hard evidence for this. Research fellow at Edinburgh University, Dr David Hamilton, published a study in the British Medical Journal in April this year of more than 4,000 people who had had knee replacement surgery. He found that three factors broadly determine their overall satisfaction rate: meeting pre-operative expectations, achieving satisfactory pain relief and having a satisfactory hospital experience.)
Now Dr Hamilton’s colleague Professor Simpson has a possible solution. With funding of £850,000 from Arthritis Research UK over four years, he and colleagues in Edinburgh, Aberdeen, Derby and Oxford are aiming to improve the poor satisfaction rates by setting up a multi-centre clinical trial targeting intensive post-operative physiotherapy at those people they think will benefit.
Currently outpatient physiotherapy following knee replacement surgery is not routine; often patients are given a home exercise package, but there isn’t usually any supervised physiotherapy provided on the NHS.
Explains Professor Simpson succinctly: “We think if targeted intensive physiotherapy is shown to work, it is deliverable on the NHS and could help a lot of people.”
The targeting of structured physiotherapy to those likely to benefit the most is what makes the Edinburgh research novel. It’s part of an increasing trend among clinicians and researchers that involves ‘stratifying’ treatment – ie targeting specific treatment at specific patients at the most appropriate time as the best way of delivering effective care.
Using a recognised patient-reported outcome measure, 5,000 patients in Edinburgh, Aberdeen, Derby and Oxford, will be assessed six weeks after knee replacement surgery. Those who are doing badly in terms of pain and function will be offered either intensive one-to-one sessions with a physiotherapist over six weeks or the usual care – advice and a home exercise sheet. Both groups will be assessed after one year.
Study co-applicant Dr Hamilton, who is working with the surgical team at Edinburgh Royal Infirmary and with physiotherapists involved in the trial, adds: “The intensive physiotherapy sessions are basically goal-orientated rehabilitation with targets, involving range-of- motion exercises, muscle strengthening and balance work. As well as the one-to-one weekly sessions with the physiotherapist, participants will also be expected to do two sessions a week at home of very detailed exercise. Those taking part will get out of it what they put in!”
There’s an important additional strand to the clinical trial. Co-applicant Professor Gary Macfarlane, professor of epidemiology at the University of Aberdeen, is also looking to be able to predict which patients benefit most from knee replacement surgery in terms of pain and function.
“We will be focusing on factors before the operation so that it helps patients and surgeons make informed decisions,” he says. “One additional aspect we will be looking at is measuring the stress-response axis through taking saliva samples from patients at different times of the day. This will allow us to examine how individuals respond to the emotional and physical stresses of undergoing surgery and whether that influences outcome.”
While the research could have major implications for the way that people are treated after knee replacement surgery to maximise patient benefit, Professor Simpson is keen to stress that, despite the dissatisfaction rates, this type of operation is nevertheless a highly effective procedure in relieving pain for a considerable number of people.
He adds: “In this research we’re trying to understand patients’ expectations of the operation as well as measuring their reported function. Patients may be feeling depressed, or have been upset by the surgical process, and this may also need to be taken into account in order to improve the patients’ outcome.”
The trial is due to start this summer.
For Michael Donnelly, intensive physiotherapy following knee revision surgery has been something of a life-saver.
Now aged 61, the formerly fit, judo-practising fireman and restaurant manager had his knee replaced in 2003. However, it started causing him problems after four years, and in 2011 he had knee revision surgery (where the replacement is itself replaced).
“I’d had ops to remove cartilage following a judo injury, then keyhole surgery, a replacement and revision. Because I’d had so many operations on my knee, the tissues and muscles in my leg were very weak and the knee was very unstable, and I was always stumbling and falling over,” Michael explains.
“I then had further surgery to have pegs and spacers put into the knee joint to stiffen it and reduce the risk of falling. It helped, but I was still getting a lot of pain.”
Michael was referred to a physiotherapist and was given a sheet of exercise to do at home, but it didn’t help.
He then went to see David Hamilton, who decided to try him on an intensive physiotherapy regime similar to that being trialled in the project. “Michael was really struggled following surgery; the revision knee replacement had corrected the underlying problem, but he had a lot of muscle dysfunction. He has really benefited from nine months of intensive physiotherapy,” says Dr Hamilton. “We’ve pushed him really hard.”
Michael Donnelly concurs. Nine months on an exercise bike and a rowing machine, using stretchy bands and running up and down the stairs have paid huge dividends. His quadriceps muscles began to strengthen, which helped to stabilise the knee, and although he is still in some pain, he is prepared to put up with that as long as he no longer stumbles and falls over when the knee collapses.
“I was plodding along getting nowhere with the normal physiotherapy,” he say. “Emma the physiotherapist was a hard task-master during the intensive sessions and I felt compelled not to let her down. I was unable to work for a few years; I couldn’t do anything because I was always stumbling and falling over, no good to anyone. I even asked the surgeon to amputate it above the knee because I felt I wasn’t getting anywhere with the knee I had – and I might as well try a false one! But now my leg is strong again and I’m the best I’m going to be.” Michael is now planning to work again.
He says: “I’m 61 but I feel there’s plenty of life left in me yet. Without doubt I’ve benefited enormously and I’d encourage other people in the same boat to do the same. But it’s hard work and it’s not for everyone. I’ve always trained hard and was very motivated, so it worked for me.”