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Appraisal of evidence base for introduction of new implants in hip and knee replacement: a systematic review of five widely used device technologies

BMJ 2014; 349 doi: (Published 09 September 2014) Cite this as: BMJ 2014;349:g5133
  1. Marc J Nieuwenhuijse, research fellow ICOR and FDA123,
  2. R G H H Nelissen, professor2,
  3. J W Schoones, information specialist4,
  4. A Sedrakyan, associate professor13
  1. 1Patient Centered Comparative Effectiveness Program and US Food and Drug Administration Medical Device Epidemiology Science and Infrastructure Center, Department of Public Health, Weill Cornell Medical College, New York, NY 10065, USA
  2. 2Department of Orthopaedics, Leiden University Medical Center, 2300 RC Leiden, Netherlands
  3. 3Office of Surveillance and Biometrics, Center for Devices and Radiological Health, FDA, Silver Spring, MD 20993, USA
  4. 4Walaeus Library, Leiden University Medical Center, 2300 RC Leiden, Netherlands
  1. Correspondence to: A Sedrakyan ars2013{at}
  • Accepted 17 July 2014


Objective To determine the evidence of effectiveness and safety for introduction of five recent and ostensibly high value implantable devices in major joint replacement to illustrate the need for change and inform guidance on evidence based introduction of new implants into healthcare.

Design Systematic review of clinical trials, comparative observational studies, and registries for comparative effectiveness and safety of five implantable device innovations.

Data sources PubMed (Medline), Embase, Web of Science, Cochrane, CINAHL, reference lists of articles, annual reports of major registries, summaries of safety and effectiveness for pre-market application and mandated post-market studies at the US Food and Drug Administration.

Study selection The five selected innovations comprised three in total hip replacement (ceramic-on-ceramic bearings, modular femoral necks, and uncemented monoblock cups) and two in total knee replacement (high flexion knee replacement and gender specific knee replacement). All clinical studies of primary total hip or knee replacement for symptomatic osteoarthritis in adults that compared at least one of the clinical outcomes of interest (patient centred outcomes or complications, or both) in the new implant group and control implant group were considered. Data searching, abstraction, and analysis were independently performed and confirmed by at least two authors. Quantitative data syntheses were performed when feasible.

Results After assessment of 10 557 search hits, 118 studies (94 unique study cohorts) met the inclusion criteria and reported data related to 15 384 implants in 13 164 patients. Comparative evidence per device innovation varied from four low to moderate quality retrospective studies (modular femoral necks) to 56 studies of varying quality including seven high quality (randomised) studies (high flexion knee replacement). None of the five device innovations was found to improve functional or patient reported outcomes. National registries reported two to 12 year follow-up for revision occurrence related to more than 200 000 of these implants. Reported comparative data with well established alternative devices (over 1 200 000 implants) did not show improved device survival. Moreover, we found higher revision occurrence associated with modular femoral necks (hazard ratio 1.9) and ceramic-on-ceramic bearings (hazard ratio 1.0-1.6) in hip replacement and with high flexion knee implants (hazard ratio 1.0-1.8).

Conclusion We did not find convincing high quality evidence supporting the use of five substantial, well known, and already implemented device innovations in orthopaedics. Moreover, existing devices may be safer to use in total hip or knee replacement. Improved regulation and professional society oversight are necessary to prevent patients from being further exposed to these and future innovations introduced without proper evidence of improved clinical efficacy and safety.


  • We thank Anna Gambaryan (AG), MPH, Lucas Romero (LR), MPA; Samantha Jacobs (SJ), BS; Sofia Lang Perez (SLP), BS for their important contributions to the review process.

  • Contributors: MJN, RGHHN, and AR were responsible for study design and concept. MJN, AR, and JWS acquired the data, which were analysed by MJN and AR. MJN, RGHHN, and AR interpreted the results. MJN and AR drafted the manuscript and are the study guarantors. MJN and AR provided statistical expertise. RGHHN, AR, and D Marinac-Dabic DM-D provided administrative, technical, or material support. All authors critically revised the manuscript and revision for important intellectual content. The authors of this article are responsible for its contents. No statement in this article should be construed as an official position of the US Food and Drug Administration.

  • Funding: MJN received a fellowship from the US FDA Medical Device Epidemiology Network’s (MDEpiNet) Science and Infrastructure Center (director AS) under the International Consortium of Orthopaedic Registries initiative (ICOR, AS received funding from the US FDA for establishing the MDEpiNet Science and Infrastructure Center and is the principal investigator of ICOR contract.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: Not required.

  • Data sharing: No additional data available.

  • Transparency: The lead authors (the manuscript’s guarantors, MJN and AS) affirm that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

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