Completed and ongoing research

Relative revision rates by cement type in cemented and hybrid total hip replacement in England and Wales.

True Mortality Rates after Total Hip Arthroplasty by method of fixation after adjustment for confounding factors- Results from the NJR in England & Wales(7th Edition).

A retrospective cohort study comparing the relative risks of revision or mortality at one and five years in patients undergoing total hip replacement.

"Current trends in primary hip arthroplasty: Influence of these trends and associated factors on survival and revision rates."

"Orthopaedic Intervention in Rheumatoid Arthritis: A retrospective analysis of cumulative incidence, prognostic markers, outcomes and cost effectiveness over a 20 year period."

Specialist Topics for the 7th Annual report carried out by the Clinical Effectiveness Unit, Royal College of Surgeons of England - London School of Hygiene and Tropical Medicine on behalf of the National Joint Registry: June 2011.

1. Evaluating capture-recapture methods to evaluate the identification of hip and knee revision surgery

A capture-recapture approach to evaluate completeness of the identification of revision procedures has been used in the last two annual reports. This method draws on information from two data sources (NJR and HES) to estimate how many revision procedures may not have been identified. The validity of the capture-recapture approach depends on whether crucial assumptions about the data sources have been met. This research explores and checks these assumptions.

2. Exploring volume-outcome relationships

Initial results of a study looking at revision rates by surgeon and unit volume suggest that revision rates vary by surgeon volume but not by hospital volume. Further work is being carried out to refine the definition of volume and to explore to what extent definitions of volume have an impact on the observed volume - outcome relationships. A further methodological issue that is being addressed is how best to allow for the multilevel nature of the data.

3. Comparing revision rates of most popular prosthesis brands

A study is carried out that compares the revision rates across the most popular brands of hip and prostheses. A crucial aspect of this study is the development and validation of a comprehensive risk adjustment method. Revision rates of the brands will be compared between and within prosthesis types.

4. Methods of thromboprophylaxis using propensity score matching and multivariable regression

The method of thromboprophylaxis after hip and knee replacement is hotly debated. We compare thromboembolic events, major haemorrhage and death after hip and knee replacement in patients receiving either aspirin or low-molecular weight heparin (LMWH). We compare propensity score matching and multivariable risk modelling as methods to adjust for differences in baseline risk.

The effect of aspirin and low-molecular-weight heparin on venous thromboembolism after hip replacement: A non-randomised comparison from information in the National Joint Registry. Jameson SS, Charman SC, Gregg PJ, Reed MR, van der Meulen JH. J Bone Joint Surg Br. 2011 Nov;93(11):1465-70.

Professor Paul Gregg, acting chair of the NJR Steering Committee says: "We are very excited about the launch of the Research website. It will become a tremendous resource for the research community and provide a repository for publicised research utilising the NJR data set."

Reason for Revision Influences Early Patient Outcomes After Aseptic Knee Revision.

Revision following patella-femoral arthroplasty. Paul N Baker, Ramsay Refaie, Paul Gregg & David Deehan. Knee Surgery, Sports Traumatology, Arthroscopy. Volume 20 number 1-January 2012.

To analyse in detail the epidemiology of revision knee replacement in England and Wales. To establish who is undergoing revision knee surgery, why it is being done and where, and what surgery is being performed. To identify any differences in the epidemiology of revision of total knee replacement and unicondylar knee replacement.

The role of pain and function in determining patient satisfaction after total knee replacement. Data from the National Joint Registry for England and Wales. Baker PN, van der Meulen JH, Lewsey J, Gregg PJ; National Joint Registry or England and Wales. J Bone Joint Surg Br. 2007;89(7):893-900.

Charlotte Davies will start an Arthritis Research UK (AR UK) funded Foundation Fellowship in July 2011, following on from her PhD, 'Three essays on the economics of hip prostheses', for which she used NJR data. NJR data was also used in her editorial for 'The Knee'.

Can choices between alternative hip prostheses be evidence based? A review of the economic evaluation literature. Davies C, Lorgelly P, Shemilt I, Mugford M, Tucker K, Macgregor A. Cost Eff Resour Alloc. 2010 Oct 29;8:20.

Which prostheses are cost-effective? Lorgelly P, Davies C, Shemilt I, Mugford M, MacGregor A. Knee.2009 Dec;16(6):419.

The Safety and Efficacy of Large-Diameter Metal-on-Metal Total Hip Arthroplasty. Bone&JointScience Vol 02, No 06 - May 2011 (PDF, 450KB)

Revision rates after primary hip and knee replacement in England between 2003 and 2006. Sibanda N, Copley LP, Lewsey JD, Borroff M, Gregg P, MacGregor AJ, Pickford M, Porter M, Tucker K, van der Meulen JH; Steering Committee of the National Joint Registry (NJR) for England and Wales. PLoS Med. 2008 Sep 30;5(9):e179. Epub 2008 Sep 2.