New pain management technique for knee replacement surgery

New pain management technique for knee replacement surgery
© iStock/Bill Oxford

One in five people experiences ongoing pain after knee replacement surgery. New research has shown a way to reduce the pain, which could save NHS time and money.

In the UK, 100,000 people have knee replacement surgery every year. A large quantity of these operations treats pain related to osteoarthritis. Around 20,000 people a year who have knee replacement surgery find that they have moderate to severe pain three months or longer after their operation.

The new research, led by the University of Bristol and North Bristol NHS Trust (NBT), was published in The Lancet Rheumatology.

STAR care pathway after knee replacement surgery

The study found the STAR care pathway (Support and Treatment After joint Replacement) reduced pain severity after knee replacement surgery. The new treatment is cost-effective and could potentially save the NHS up to £14 million per year through reduced inpatient admissions.

The study found patients who received the STAR care pathway had:

  • Less pain severity and impact on daily life at both six and 12 months after treatment (nine and 15 months after surgery),
  • Half the number of hospital re-admissions,
  • Reduced length of hospital stays for any inpatient admissions three months after surgery,
  • Less unpaid time off work.

The five-year STAR programme aimed to find ways to improve the care and support that people with ongoing pain receive after knee replacement surgery. The programme, funded by the National Institute for Health Research (NIHR), designed and tested a new treatment in a randomised controlled trial in eight UK hospitals.

The programme analysed how likely patients are to experience ongoing knee pain after their operation and discovered why patients do not seek help. The research team developed a new treatment – a care pathway — for patients and compared how patients did on the STAR care pathway when contrasting with a control group who continued with the usual care.

STAR care pathway:

  • Three months after surgery, patients attended an hour-long clinic, run by specially trained health care professionals,
  • Detailed pain questionnaires were filled out, X-rays were taken, and a blood test for infection. If needed, patients were referred for further ongoing treatment,
  • Patients received up to six phone calls over the next 12 months, ensuring they had their referral and checking how they were doing.

STAR trial

Rachael Gooberman-Hill, lead researcher for the STAR programme, Professor of Health and Anthropology and Director of Bristol’s Elizabeth Blackwell Institute, said: “People have a knee replacement to relieve their pain and it’s immensely disappointing if they find that they have long-term pain afterwards. Unfortunately, one in five people who have knee replacement have long-term pain afterwards – that is around 20,000 people each year in the UK alone.

“As a research team, we wanted to do something that would help. We found that our new STAR care pathway had a positive impact on people’s pain. People who had long-term pain after their knee replacement and who were given STAR had less pain and the pain interfered less with their lives one year later. People told us that STAR helped them to feel supported, to find out more about their pain and STAR meant that they were able to get further treatment that was tailored to their pain. We are enormously pleased with our research findings because it should make a real difference to people who find that they have pain after their knee replacement surgery.”

Brenig, a participant in the STAR trial, explained: “As part of the STAR trial, you have tailored physiotherapy appointments. At my three-month review with a STAR physiotherapist, I was having a problem not being able to straighten my leg out. She gave me some simple exercises, which worked and straightened the leg out. Occasionally I have problems at the back of the knee, then I do the exercises and it goes back to normal. So that was a very positive side of what we did.

“I felt that being part of the STAR trial gave me access to a specialist physiotherapist. Her knowledge was far, far superior, and specific to my issue. Some mornings I get up and feel on top of the world and then the following day, I have leg pain. Eventually, you get to accept it, but doing the exercises helps.”

The study has benefited from Bristol’s Musculoskeletal Research Unit’s patient involvement group, PEP-R (Patient Experience Partnership in Research), who worked closely with the STAR research team to develop the design of the programme.

Dr Vikki Wylde, Associate Professor in Musculoskeletal Health at Bristol Medical School (THS), and co-author, added: “The new STAR care pathway provides benefit to people with pain at three months after knee replacement surgery, but we still need more research to understand how we could prevent people from developing this pain.

“High-quality research to pre-operatively identify patients at high risk of developing pain after their operation is needed. These patients could be offered treatments to increase their chance of a good outcome after knee replacement surgery.”

Nick Howells, Consultant Orthopaedic Knee Surgeon at NBT and Honorary Senior Lecturer at Bristol Medical School: THS, continued: “Knee replacement surgery is a great operation that changes the lives of many people suffering from knee osteoarthritis, improving pain, function and quality of life, however, a proportion of people are left with ongoing pain. To have developed an intervention that has been shown to make a difference for some of these people are really satisfying for our team and a great step forward in treatment.

“We have now successfully introduced the STAR care pathway into our NHS clinical care pathway at North Bristol and hope it will be adopted in other centres across the NHS in the future.”



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