A recent study from the University of Bristol has revealed that hip implants featuring a delta ceramic or oxidized zirconium head, combined with a highly crosslinked polyethylene liner or cup, exhibit the least likelihood of needing revision surgery within 15 years post-operation. This research aims to aid hospitals, surgeons, and patients in selecting the most suitable hip implants for replacement surgeries.
The study sought to identify hip implant materials that carry a higher risk of requiring revision, thereby assisting orthopedic surgeons and patients in making informed decisions regarding their surgery by highlighting options with the lowest revision risk.
The independent research, published today in PLOS Medicine, was funded by CeramTec and received support from the National Institute for Health and Care Research (NIHR) along with the NIHR Bristol Biomedical Research Centre (Bristol BRC).
Researchers analyzed data from the National Joint Registry (NJR), which included records from 1,026,481 hip replacement operations conducted in both NHS and private sectors in England and Wales over a period of up to 15 years (from 2003 to 2019).
Upon reviewing the NJR data, the research team discovered that the likelihood of needing a revision after a hip replacement is markedly affected by the materials used in the bearing surface. The bearing surfaces are the sections of the artificial hip joint that move relative to each other during activity.
Findings indicated that implants with a delta ceramic or oxidized zirconium head and a highly crosslinked polyethylene liner or cup had the lowest revision rates over the 15 years following hip replacement surgery.
This conclusion was reaffirmed when the team examined the specific causes that led to revision surgeries being required. The data showed that 20,869 patients (2% of the total) underwent revision surgeries after their initial hip replacement.
Dr. Erik Lenguerrand, a Senior Lecturer in Medical Statistics and Quantitative Epidemiology at the University of Bristol, and a senior author of the study, stated: “Our research indicates that the risk of hip replacement revision is influenced by the materials used in the implants. The implants with delta ceramic or oxidized zirconium heads combined with a highly crosslinked polyethylene liner or cup carry the lowest risk of revision.”
“More research is needed to explore how implant materials correlate with risks of rehospitalization, other re-operations, mortality, and the overall cost-effectiveness of these materials.”
Michael Whitehouse, a Professor of Trauma and Orthopaedics at Bristol Medical School and senior clinical lead for the paper, noted: “This study utilized data from one of the world’s largest registries encompassing all public and private healthcare sectors in England and Wales, which enhances the applicability of our findings compared to previous data that had limitations due to broad categorizations of implant types or smaller sample sizes. It underscores the significance of examining the complete structure formed by the combination of implants used in a hip replacement rather than isolating each component.”
“Our results will assist hospitals, surgeons, and patients in selecting hip implants and their combinations that pose the least risk of revision after the initial surgery.”
Tim Wilton, the Medical Director of the National Joint Registry (NJR), added: “We are continually pleased when NJR data is leveraged for impactful research like this, providing meaningful insights to guide surgeons and patients in their decision-making. The NJR data offers a unique avenue for assessing the long-term performance of various hip implant materials.”
“By tracking combinations of materials and their associated revision rates, this study emphasizes the critical role of implant material selection on surgical outcomes. This can help ensure that the materials chosen are optimized for durability and patient well-being. Surgeons should closely examine these findings regarding their implant options and incorporate this information into pre-operative discussions with their patients as the demand for joint replacements rises, this insight is invaluable for reducing revision surgeries.”
It is important to note that this research was not a randomized controlled trial, meaning that not all factors influencing revision risk could be adequately controlled.
The classification of hip implants within national joint replacement registries often oversimplifies the variety of materials, which can obscure the differences in revision risks associated with distinct implant types.
Joint replacement surgery is a widespread and effective option for addressing various musculoskeletal issues like osteoarthritis and acute trauma, with over 110,000 procedures performed annually in the UK. Projections show that by 2060, the demand for joint replacements could increase by nearly 40% from current figures. These procedures are designed to last, with over half of hip and knee replacements remaining functional beyond 25 years.
The research team extends gratitude to the patients and staff at hospitals across England, Wales, and Northern Ireland for their contributions to the NJR data, along with recognition to the Healthcare Quality Improvement Partnership, the NJR Research Committee, and NJR staff for their support in facilitating this research.
