Arthritis of the knee: comparing total and partial knee replacement
Published on 30 January 2009
Over 50,000 people with severe arthritis undergo knee replacement surgery each year in the UK.1,2,3 Most have a total knee replacement. However, around 10% of those who undergo surgery have arthritis that affects only the area around the knee-cap.4 For these people, it’s unclear whether it’s best to replace the whole knee or just the area around the knee-cap. Researchers are investigating which type of surgery is best in a clinical trial.
Contents
What's the problem and who does it affect?
Unclear evidence
Every year in the UK, over 50,000 people have such bad arthritis in their knee that they choose to undergo knee replacement surgery.1.2.3
Around 5,000 of those who undergo surgery have arthritis that is limited to the area around the knee-cap.1,2,3,4 They suffer pain in the knee that gets worse with any movement. Activities like climbing stairs or standing up from a chair can be excruciatingly painful. This can be extremely frustrating, limiting day-to-day activities and participation in sports, and sometimes forcing people to give up work.
Knee replacement surgery can free people from pain, meaning they can become much more active again. Most people have the whole knee joint replaced, even if their arthritis is limited to the area around the knee-cap.
However, it is possible to replace just the area around the knee-cap. Early trials of this technique gave unsatisfactory results, but more recent improvements mean it is now unclear which type of surgery is best. The lack of evidence means choosing between total and partial knee replacement presents a very real conundrum for surgeons and their patients.
What is the project trying to achieve?
Clinical trial
Around 60 people with arthritis in the area around the knee-cap are taking part in a clinical trial. They are being randomly allocated to two treatment groups: half are having a total knee replacement (which is known as total knee arthroplasty) and the other half are having just the area around the knee-cap replaced (which is called patellofemoral arthroplasty).
Researchers are assessing the volunteers before surgery and at four time points over the following year. They are comparing the pros and cons of each type of surgery – assessing effects on knee function, quality of life, levels of disability and physical activity, and any complications.
To avoid bias in the assessments, neither the volunteers, nor the researcher who’s assessing them will know which type of surgery each person has had.
What are the researchers' credentials?
| Project Leader | Mr M Costa PhD |
|---|---|
| Project team | Dr Juul Achten MSc PhD Mr Nick Parson BSc MSc PhD Professor Damian Griffin MA MPhil FRCS Mr Tim Spalding MBBS FRCS |
| Location | Warwich Medical School, University of Warwick, University Hospitals Coventry and Warwickshire NHS Trust |
| Other locations | University Hospital at Walsgrave, Coventry |
| Duration | 3 years |
| Grant awarded | 30 October 2008 |
| Start date | 1 May 2009 |
| End date | 30 April 2013 |
| Grant amount | £91,470.00 |
| Grant code | AP1170,GN1737 |
The project leader, Mr Matt Costa, is an experienced surgeon and researcher based at Warwick Orthopaedics. The unit is rapidly developing an international reputation as a centre of excellence for both surgery and research in three important fields: joint replacement surgery, treating sports injuries and surgery for traumatic injuries. A large number of the unit’s experienced surgeons will be involved in this study.
The unit’s research focus is on clinical trials of new and innovative interventions – investigating different approaches to joint replacement surgery and to healing fractured or ruptured bones and tendons.
Who stands to benefit from this research and how?
More informed decision making
This research will benefit people who need surgery to treat severe arthritis that is limited to the area around their knee-cap, and that does not affect the rest of their knee joint – that’s 5,000 people every year in the UK.1,2,3,4
The researchers aim to determine which type of surgery seems best – replacing the whole knee joint or just the area around the knee cap. They hope to give sufferers and their surgeons high-quality evidence on the relative benefits of the two treatments, so that everyone is in a better position to choose the best type of surgery for them.
Replacing the whole knee joint is currently the gold standard. However, in theory, replacing just the area around the knee-cap might have important benefits. It preserves more of the person’s own knee joint – preserving bone, ligaments and so on – and it is less invasive, meaning recovery ought to be quicker. Results of this study will provide objective evidence to help prove or disprove this theory.
References
- National Joint Registry for England and Wales. 5th Annual Report. www.njrcentre.org.uk
- National Joint Registry for England and Wales. 4th Annual Report. www.njrcentre.org.uk
- National Joint Registry for England and Wales. 3rd Annual Report. www.njrcentre.org.uk
- Davies AP, Vince AS, Shepstone L, Donell ST, Glasgow MM. The radiologic prevalence of patellofemoral osteoarthritis. Clin Orthop Relat Res 2002; 402:206-12.
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