Healthcare (Commonwealth Union) – A University of Bristol-led study has found that hip implants made with a delta ceramic or oxidized zirconium head paired with a highly crosslinked polyethylene liner or cup show the lowest risk of revision within 15 years after surgery. These findings may aid hospitals, surgeons, and patients in selecting hip implant materials that are less likely to require follow-up surgeries.
The study aimed to assess the likelihood of revision for various hip implant materials, supporting orthopaedic surgeons and patients in making well-informed choices before surgery. This independently conducted research, published in PLOS Medicine on November 7, was funded by CeramTec and supported by the National Institute for Health and Care Research (NIHR) and the NIHR Bristol Biomedical Research Centre (Bristol BRC).
Researchers examined data from the National Joint Registry (NJR) covering 1,026,481 hip replacements performed in NHS and private hospitals in England and Wales, tracking outcomes for up to 15 years post-surgery (2003 to 2019).
The analysis revealed that the materials used in the bearing surfaces, the moving parts of an artificial hip joint, play a key role in the risk of revision surgery. Hip implants featuring delta ceramic or oxidized zirconium heads combined with highly crosslinked polyethylene liners or cups had the lowest risk of needing revision. This was further validated by examining specific reasons for revision, which affected 20,869 patients (2 percent) following their initial hip replacements.
Dr Erik Lenguerrand, who is a Senior Lecturer in Medical Statistics and Quantitative Epidemiologist in the Bristol Medical School: Translational Health Sciences (THS) at the University of Bristol, and a senior author on the paper, says “Our research has found the risk of hip replacement revision depends on the hip implant materials used in the original surgery. The lowest risk of revision are from implants with delta ceramic or oxidised zirconium head and a highly crosslinked polyethylene (HCLPE) liner or cup.
“Further research is needed to find out the association of implant materials with the risk of rehospitalisation, re-operation other than revision, mortality and the cost-effectiveness of these materials.”
Professor Michael Whitehouse, an expert in Trauma and Orthopaedics at Bristol Medical School and senior clinical lead for the study, stated that their research leverages data from one of the world’s largest registries, encompassing both public and private healthcare sectors in England and Wales. This makes the findings more broadly applicable compared to previous studies, which were often limited by smaller sample sizes or broad groupings of implant types. It underscores the importance of evaluating the complete implant structure used in hip replacements, rather than just focusing on individual components.
Professor Whitehouse further indicated that the results will support hospitals, surgeons, and patients in selecting hip implants and combinations with the lowest risk of needing revision after the initial hip replacement surgery.
This research was not a randomized controlled trial, which means it wasn’t possible to control all the factors that could influence revision risk.
In national joint replacement registries, hip implants are often grouped broadly, which can obscure differences in revision risks among specific implant materials within those categories.
Joint replacement surgery, frequently used to treat conditions like osteoarthritis and acute trauma, is both common and highly effective, with over 110,000 procedures performed each year in the UK. By 2060, demand for these surgeries is expected to rise by nearly 40% from current levels. Joint replacements are generally durable, with more than half of hip and knee replacements lasting over 25 years.
The research team extended their gratitude to the patients and hospital staff across England, Wales, and Northern Ireland who contributed data to the NJR, as well as the Healthcare Quality Improvement Partnership, the NJR Research Committee, and NJR staff for their support in facilitating this research.
