Factors associated with implant survival following total hip replacement surgery
Jonathan Thomas Evans, Ashley William Blom, Andrew John Timperley, Paul Dieppe, Matthew James Wilson, Adrian Sayers, Michael Richard Whitehouse
Abstract
Background
Nearly 100,000 people underwent total hip replacement (THR) in the United Kingdom in 2018, and most can expect it to last at least 25 years. However, some THRs fail and require revision surgery, which results in worse outcomes for the patient and is costly to the health service. Variation in the survival of THR implants has been observed between units and reducing this unwarranted variation is one focus of the “Getting it Right First Time” (GIRFT) program in the UK. We aimed to investigate whether the statistically improved implant survival of THRs in a high-performing unit is associated with the implants used or other factors at that unit, such as surgical skill.
Introduction
Total hip replacement (THR) is one of the most successful operations of our time with nearly 100,000 performed in England, Wales, Northern Ireland, and the Isle of Man in 2017 [1, 2]. They have been shown in general to last about 25 years, but despite this, there is still variation in the survival of implants across the UK [2, 3]. THR components may require changing (via revision surgery) for one of several reasons including infection, wear, loosening, fracture, or instability [2]. The need for future revision surgery can be influenced by preoperative patient factors, implant factors, and surgical factors [4, 5].
Methods
We aimed to compare the cumulative revision estimates between the RD&E and the rest of the country to investigate whether “better than expected” outcomes were due to the implants used or because of other unit factors.
The NJR is a mandatory national audit of joint replacement activity. After gaining written consent, operations are reported to the NJR by the healthcare provider at the time of surgery. The dataset consisted of 981,269 linked primary THRs performed in England and Wales between 1 April 2003 and 31 December 2017 with consent for data linkage. Data were censored either by death or administratively on 31 December 2017. After exclusion of THRs with incomplete or inconsistent data or using metal-on-metal bearings, we were left with 664,761 primary THRs, in which osteoarthritis was the only indication for THR. Reasons for exclusion at each stage are shown in Fig 1.
Discussion
After 13.9 years, both crude and adjusted cumulative revision estimates showed better implant survival when THRs were performed at the RD&E compared with elsewhere in the country. In analyses adjusted for age, sex, and ASA score, these differences attenuated after restricting to only cemented implants and disappeared when only THRs using the same implant combinations as the RD&E were analyzed. This suggests that implant choice is responsible for the “better than expected” results at the RD&E and not unit (or surgeon) factors.
Acknowledgments
We thank the patients and staff of all the hospitals in England, Wales and Northern Ireland who have contributed data to the National Joint Registry.
The Healthcare Quality Improvement Partnership (HQIP) and/or the NJR take no responsibility for the accuracy, currency, reliability, and correctness of any data used or referred to in this report, nor for the accuracy, currency, reliability, and correctness of links or references to other information sources and disclaims all warranties in relation to such data, links, and references to the maximum extent permitted by legislation.
Citation: Evans JT, Blom AW, Timperley AJ, Dieppe P, Wilson MJ, Sayers A, et al. (2020) Factors associated with implant survival following total hip replacement surgery: A registry study of data from the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man. PLoS Med 17(8): e1003291. https://doi.org/10.1371/journal.pmed.1003291
Academic Editor: Rob G.H.H Nelissen, Leiden University Medical Center, NETHERLANDS
Received: January 17, 2020; Accepted: July 30, 2020; Published: August 31, 2020
Copyright: © 2020 Evans et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: Data cannot be shared publicly. Data are available from the NJR research subcommittee researchers who meet the criteria for access to confidential data. Access to the data used in this study can be requested via njrresearch@hqip.org.uk. Full details of how to request NJR data for research can be found at: http://www.njrcentre.org.uk/njrcentre/Research/Research-requests.
Funding: This study was supported by the NIHR Biomedical Research Centre at University Hospitals Bristol and Weston NHS Foundation Trust and the University of Bristol. JTE was supported by the joint National Joint Registry of England, Wales, Northern Ireland and the Isle of Man and Royal College of Surgeons of England Fellowship. AS was supported by a MRC strategic skills fellowship: MRC Fellowship MR/L01226X/1 The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: AB and MRW have received a research grant from Stryker for an unrelated knee replacement trial, MRW’s institution has been paid for work he has done developing and delivering educational presentations for DePuy and Heraeus. MJW and AJT receive institutional support from Stryker for research into and royalties relating to the Exeter hip replacement system from Stryker; there are no other relationships or activities that could appear to have influenced the submitted work.
Abbreviations: ASA, American Society of Anesthesiology; FPSA, flexible parametric survival analysis; GIRFT, Getting it Right First Time; HQIP, Healthcare Quality Improvement Partnership; NHS, National Health Service; NJR, National Joint Registry for England, Wales, Northern Ireland and the Isle of Man; RD&E, Royal Devon & Exeter NHS Foundation Trust; RMST, restricted mean survival time; THR, total hip replacement.
