The National Joint Registry of England, Wales & Northern Ireland (Meeting report)

The Northern Ireland local group of the RSS held an online meeting on Wednesday, 15 March 2023 at 1pm (GMT), using MS Teams.

The speaker was Dr. Linda Hunt, University of Bristol, UK.

Dr Hunt described the history, operation and outputs of the National Joint Registry (NJR) in Bristol.
The Registry, which opened in 2003, was set up to record total hip and knee replacements (implants) in England and Wales. The aims were to:

'...collect data to provide early warning of issues related to patient safety and to improve quality/cost effectiveness, by monitoring and reporting on outcomes and supporting and enabling related research.'

Other joints were added later: ankles (April 2010) and elbows and shoulders (April 2012). Submission of data from NHS Units became mandatory in 2011, but it had always been so for Units operating in the independent sector.

Over the years, the coverage has increased, Northern Ireland started to submit data in February 2013, the Isle of Man in July 2015, and Guernsey in November 2019. Today, the Registry contains information on over 3.5 million procedures, making it the largest Joint Registry in the world. Surprisingly, Scotland has not participated in the NJR.

From April 2014, the NJR has been funded by a subscription service with NHS trusts and independent providers making payments based on their surgical volumes for the previous year. It is hosted by the Healthcare Quality Improvement Partnership (HQIP), in London, and has a director of operations, a management team, and a steering committee comprising representation from orthopaedic surgeons, implant device manufacturers, patients, NHS and independent health sectors. The database is managed, separately, by NEC Software Solutions, UK, and the statistical analyses are conducted by teams in the Universities of Bristol and Oxford.

Detailed data are recorded on the: patient (age, sex, BMI, ASA, etc.), implant (nature, size, composition, brand and manufacturer, etc.) and operation (fixation/cement, anaesthetic, surgical approach, thromboprophylaxis, etc.). Annual statistical reports and research outputs are produced in relation to the following outcomes Revision (replacement/repair), Death, and PROMs (eg, Oxford hip/knee scores, VAS, etc.). The basic `Unit' of analysis is the implant (not the patient), except when dealing with mortality.

For example, in the 1999 report there were 1,344,357 primary hips, from 478 units, linked to 40,387 first revisions and the overall cumulative revision rate was 2.1% at 5 years and 4.1% at 10 years. Cumulative revision worsened between 2003 and 2008, then improved, due likely to the resurfacing of metal-on-metal (MoM) joints. Cumulative revision rates were higher in younger recipients and in men rather than women, in each age band (excluding MoM hips). Reasons for infection, included: dislocation, pain (early), aseptic loosening (after 5 years) and others.

Dr Hunt then described areas of research tackled by the NJR. There was early work on hip implant survival, ie, on 'time to first revision' and 'time to first resurfacing' in stemmed MOM joints, compared to other types, using flexible parametric survival modelling (Lancet). The issue of an increased risk of cancer following implant was addressed in two further papers: (a) risk of cancer in the first 7 years following MoM replacement compared with other types and the general population (BMJ), and (b) related, research, but dealing with resurfacing of MoM joints at 11.75 years follow-up (PLOS ONE). Both papers showed no significant increase. Similar research was undertaken on knees. The NJR team also investigated other areas including mortality, showing that for hips the hazard rate for death declined up to 90 days after the primary operation, the cumulative 90-day mortality increased with age at operation, but was worse in men (Lancet), and the decline in 90-day mortality over the period 2003-2011 was more than expected based on E&W rates. There were many other interesting findings which cannot be included here due to space constraints, but the links below will repay perusal.

This insightful and highly interesting talk was received with acclaim and the audience showed their appreciation in the usual way.

Later, the Chair thanked the speaker for a very stimulating talk and discussion. She closed the meeting by thanking everyone for their attendance and support.

Related Links:
For more information about the NJR, check out: and read the 19th Annual Report, and more here.

Written by Gilbert MacKenzie
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