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Assessing the non-inferiority of prosthesis constructs used in hip replacement using data from the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man: a benchmarking study
  1. Kevin C Deere1,
  2. Michael R Whitehouse1,2,
  3. Martyn Porter3,
  4. Ashley W Blom1,2,
  5. Adrian Sayers1,4
  1. 1 Musculoskeletal Research Unit,Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
  2. 2 National Institute for Health Research,Bristol Biomedical Research Centre, University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol, UK
  3. 3 Centre for Hip Surgery, Wrightington Hospital, Wigan, UK
  4. 4 Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
  1. Correspondence to Adrian Sayers; adrian.sayers{at}


Objectives To investigate the relative performance of hip prosthesis constructs as compared with the best performing prosthesis constructs and illustrate the substantial variability in performance of currently used prostheses.

Design A non-inferiority study.

Setting The National Joint Registry for England, Wales, Northern Ireland and the Isle of Man (NJR).

Participants All patients with a primary total hip replacement registered in the NJR between 1 April 2003 and 31 December 2016.

Main outcome measures Kaplan-Meier failure function for hip prosthesis constructs. Failure difference between best performing construct and remaining constructs.

Methods Using a non-inferiority analysis, the performance of hip prosthesis constructs by brand were compared with the best performing contemporary construct. Construct failure was estimated using the 1-Kaplan-Meier survival function method, that is, an estimate of net failure. The difference in failure between the contemporary benchmark and all other constructs was tested.

Results Of the 4442 constructs used, only 134 had ≥500 procedures at risk at 3 years postprimary, 89 of which were not demonstrated to be inferior to the benchmark by at least 100% relative risk. By 10 years postprimary, there were 26 constructs with ≥500 at risk, 13 of which were not demonstrated to be inferior by at least 20% relative risk.

Even fewer constructs were not inferior to the benchmark when analysed by age and gender. At 5 years postprimary, there were 15 constructs in males and 11 in females, aged 55–75 years, not shown to be inferior.

Conclusions There is great variability in construct performance and the majority of constructs have not been demonstrated to be non-inferior to contemporary benchmarks. These results can help to inform patients, clinicians and commissioners when considering hip replacement surgery.

  • hip arthroplasty
  • non-inferiority
  • national joint registry
  • benchmarking
  • medical devices

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  • Contributors AS, MRW and AWB conceived the study. KD, AS and AWB designed the study. The data were extracted by Northgate (Hemel Hempstead, UK). KD and AS managed and analysed data. MRW, AS, MP and AWB reviewed the published work. All authors critically inputted into final design of the study, interpreted the data and cowrote the manuscript. AS is the guarantor and attests on behalf of the authors that the manuscript is a true and transparent reflection of the study without omissions.

  • Funding Posts of members of the research team are funded by a contract grant from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. This study was also supported by the NIHR Biomedical Research Centre at the University Hospitals Bristol NHS Foundation Trust and the University of Bristol. AS is funded by an MRC Strategic Skills Fellowship MR/L01226X/1. The sponsor of the study had no role in the study design, data collection, analysis, interpretation or writing of the final report. KD and AS had full access to all of the data and AS had final responsibility for manuscript submission.

  • Disclaimer The views expressed represent those of the authors and do not necessarily reflect those of the NHS, the National Institute for Health Research, the Department of Health, the National Joint Registry Steering Committee or Healthcare Quality Improvement Partnership, who do not vouch for how the information is presented.

  • Competing interests None declared.

  • Ethics approval Pseudo anonymised analysis of NJR data is considered as secondary use of clinical registry data, under HRA guidance this does not require formal ethical approval. However, all research projects are internally approved by the NJR. The full NJR privacy notice can be found online (

  • Provenance and peer review Not commissioned; peer reviewed for ethical and funding approval prior to submission.

  • Data sharing statement Access to data is available from the National Joint Registry for England and Wales.

  • Patient consent for publication Not required.

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