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People’s long-term pain after knee surgery is reduced, new treatment has shown

Press release issued: 27 January 2022

With one in five people experiencing ongoing pain long after knee replacement surgery, new research, led by the University of Bristol and North Bristol NHS Trust (NBT) and published in The Lancet Rheumatology today [27 January], has shown a way to help reduce people’s continuing pain that could also save the NHS time and money too.

One hundred thousand knee replacement surgeries are carried out in the UK every year.  Most of these operations take place to treat pain related to osteoarthritis. Unfortunately, each year, around 20,000 people who have knee replacement surgery to relieve their pain find that they have moderate to severe pain three months or longer after their operation, which impacts on their everyday lives. 

The study found the STAR care pathway (Support and Treatment After joint Replacement) reduces pain severity, the amount pain interferes with people’s lives and is cost-effective.  The new treatment 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 stay for any inpatient admissions three months after surgery
  • Less unpaid time off work

The aim of the five-year STAR programme was to find ways to improve the care and support that people with ongoing pain receive. 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 looked at how likely patients are to get ongoing knee pain after their operation and discovered why patients don’t 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 compared with a control group who had the usual care.

STAR care pathway:

  • Three months after surgery patients attended an hour-long clinic, ran by specially trained health care professionals
  • Detailed pain questionnaires were filled out and X-rays were taken as well as 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, making sure they had their referral, and to check how they were doing

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."

Brenig, a participant on 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 actually 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 greatly 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: Translational Health Sciences (THS), and co-author, added: "The new STAR care pathway provides benefit to people with pain at three months after knee replacement, 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."

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 with knee osteoarthritis, improving pain, function and quality of life, however, a proportion of people are left with ongoing pain. To have developed an intervention which has been shown to make a difference for some of these people is 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."


'The STAR care pathway for patients with pain at three months after total knee replacement: a multicentre, pragmatic randomised controlled trial' by Vikki Wylde, Rachael Gooberman-Hill et al in The Lancet Rheumatology

Further information

This study is funded by the National Institute for Health Research (NIHR) through their Programme Grants for Applied Research scheme (Grant Reference Number RP PG 0613 20001).

The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care.

STAR care pathway case study: Brenig
I needed knee replacement surgery because I was having problems at work.  My kneecap was collapsing on me, and I was in a lot of pain and unable to complete the fitness assessment for police officers, the role I was performing at the time.

The first time I really noticed how my knee was affecting me and my work was as a Custody Sergeant.  Just turning on it would drop me straight to the floor. The pain was so acute, and my knee would go up like a balloon straight away.

I was having pain after surgery and when I saw a STAR physiotherapist at my three-month review, I was given some simple exercises as I was having problems straightening my leg out, which have worked.  When I have the occasional problem, I do the exercises and my knee goes back to normal.

Being part of the STAR trial has given me access to a specialist physiotherapist, which has been very positive.  Their knowledge was far, far superior and specific to my issue.

My recovery has been a journey. Some mornings I feel on top of the world and then the following day I have leg pain but eventually you get to accept it.

About the National Institute for Health Research (NIHR)
The mission of the National Institute for Health Research (NIHR) is to improve the health and wealth of the nation through research. We do this by:

  • Funding high quality, timely research that benefits the NHS, public health and social care;
  • Investing in world-class expertise, facilities and a skilled delivery workforce to translate discoveries into improved treatments and services;
  • Partnering with patients, service users, carers and communities, improving the relevance, quality and impact of our research;
  • Attracting, training and supporting the best researchers to tackle complex health and social care challenges;
  • Collaborating with other public funders, charities and industry to help shape a cohesive and globally competitive research system;
  • Funding applied global health research and training to meet the needs of the poorest people in low and middle income countries.

NIHR is funded by the Department of Health and Social Care. Its work in low and middle income countries is principally funded through UK Aid from the UK government.

About North Bristol NHS Trust (NBT)
North Bristol NHS Trust (NBT) runs healthcare services from Southmead Hospital, Cossham Hospital, Bristol Centre for Enablement as well as satellite sites across Bristol, North Somerset and South Gloucestershire. 

As well as providing high-quality healthcare to the local population, NBT is a centre of excellence in the South West and beyond in a range of services and major specialities including neurosciences, orthopaedics and plastic surgery. 

NBT also run the Severn Major Trauma Network caring for the most seriously injured patients from injury to rehabilitation. The Network covers the Severn region and includes 2.3 million adults over 800,000 children. 

NBT remains a leader in health research that aims to answer important clinical questions. We are currently managing £30 million grants awarded to deliver new programmes of research.

Our pioneering treatments and advances in care have won international recognition, placing us at the forefront of medical knowledge.

About the Elizabeth Blackwell Institute
Nurturing research. Improving health.

The Elizabeth Blackwell Institute drives innovation in research to improve health for all. It nurtures interdisciplinary research to address the complex health challenges facing us today.

The institute focuses on:

  • Supporting the next generation of health researchers
  • Connecting people to develop interdisciplinary research
  • Including everyone in research so the research can benefit all.
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