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Home › News › First national study reveals strength in joint replacement

First national study reveals strength in joint replacement

02 September 2008

The quality of hip and knee replacement operations in England compares favourably to the rest of the developed world, but further research into which patients should get which type of operation is needed. These are among the findings of the first ever study of joint replacement tracking over half of all such operations carried out on the NHS in England over three and a half years – more than 150,000 patients.

The study was undertaken by researchers from the Royal College of Surgeons of England and only possible thanks to new data from the National Joint Registry which was established in 2002. The research focused on “revision rates” – the number of people who needed further corrective surgery after their joint operation – and key findings included:

  • Overall, only one in 75 (1.4 per cent) patients required revision to their hip or knee operation within three years.
  • Revision rates were higher for ‘hip resurfacing’ and ‘unicondylar knee’ – both newer procedures and further research over longer timescales is needed to find out if this variation persists, why and narrow down which patients would most benefit from these operations.
  • This figure is lower than other countries who run national joint registries with Norway, Australia and Sweden all reporting higher rates – however, each registry gathers statistics differently so it is currently difficult to make absolute comparisons. National registries should aim to harmonise to make results more comparable.
  • We should be more ambitious - NICE currently sets the revision rate benchmark for approving new brands and designs of hip prostheses at ten per cent over ten years. This study indicates they could be setting a higher quality threshold as current practice is already well within that benchmark.

The study*, published today (September 2, 2008) in the open-access journal PLoS Medicine, linked records from the National Joint Registry (NJR) and the Department of Health’s Hospital Episodes Statistics (HES) between April 2003 and September 2006 to give the most complete picture ever of how hip and knee replacement patients fare.

“Hip and knee operations are among the most commonly performed surgical procedures in the country and there are many different types of prosthesis and operative techniques with new ones being developed all the time. It is a pleasure to note just how good these results are, a credit to the nation’s orthopaedic surgeons and their teams,” said John Black, President of the Royal College of Surgeons.

“By having a national registry and linking with routinely collected patient data we can quickly evaluate these technical innovations and ensure patients get the best possible outcomes from their surgery, even better than they are at the moment.”

“The contribution which the NJR is able to make to good practice and improved patient care, is now significant,” said Bill Darling, Chair of the NJR Steering Committee. “With one of the largest databases of its kind in the world, the quality, type and accuracy of analysis now available from the NJR is of enormous value, as this study demonstrates. We are justifiably proud that the NJR has developed into a real tool for excellence, resource for clinical audit, and can influence improvement in best practice.”

“This study demonstrates what can be achieved by linking the NJR with HES data. The paper convincingly shows that hip and knee replacements continue to improve in their success rates and that our results are amongst the finest in the world,” said Stephen Cannon of the British Orthopaedic Association. “The utilisation of the NJR shows that there are concerns with hip re-surfacing and the use of uni-condylar prostheses which require further study regarding their clinical indications. The British Orthopaedic Association will continue to encourage research specific into these areas.”

Revision Rates after Primary Hip and Knee Replacement in England between 2003 and 2006 will be available from Sept 2nd on the PLoS website here:


1.    The Royal College of Surgeons of England is committed to enabling surgeons to achieve and maintain the highest standards of surgical practice and patient care. Registered charity number: 212808. For more information please visit

2.    If you have any queries please contact:

Matthew Worrall – Email:; T: 020 7869 6047

Elaine Towell – Email:; T: 020 7869 6045

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