An evaluation of knee arthroplasty fixation in an evolving challenging population
Many people with severe knee pain caused by osteoarthritis have an operation called a knee replacement, replacing the damaged bone with an artificial joint. Over 100,000 knee replacements are performed annually in the United Kingdom with this number expected to increase substantially by 2030. Up to one fifth of patients experience persistent pain and are unsatisfied with their knee replacement.
Knee replacements can be secured in place using cement or without cement (uncemented). Most surgeons currently use cement although some do not, with no overall opinion on which is better. Increasing numbers of patients who are overweight or younger need a knee replacement. There are concerns that cement may not last a patient’s lifetime with studies showing younger and overweight patients do worse with cemented knee replacements. Furthermore, cement setting during the operation gives off considerable heat which may damage surrounding structures and contribute to long term pain.
One solution is to use a more natural knee replacement without cement. Uncemented knee replacements have shown advantages over cemented in small studies, including reduced surgery times, blood loss and infection risk. This may reduce the chances of serious illness, disability and death.
Given the changing population needs, and input from our patient steering groups, we intend to complete a full comparison of cemented and uncemented knee replacements for the first time using big data.
Large datasets from the National Joint Registry (NJR) alongside data from NHS Digital will be used during this study. The personal identifiers of patients who had knee replacement surgery (study cohort) and consented for their details to be stored in the NJR will be securely transferred to NHS Digital. NHS Digital will then extract details of all hospital admissions (HES) for the study cohort and Patient Recorded Outcome Measures (PROMS). NHS Digital will securely transfer their data to the University of Oxford as pseudonymised data (i.e. all identifiers will be removed and replaced with a unique patient ID). The NJR will securely transfer their pseudonymised data from its records to the University of Oxford using the same unique patient ID so that the data can be linked by the University of Oxford and processing in such a way that researchers will not be able to identify patients.
We will analyse data routinely collected hospital data to compare:
- How long each cemented and cementless knee replacements last.
- How cemented and cementless knee replacements fail.
- What the patient pain/functional status are for cemented and cementless replacements.
- The cost effectiveness of cemented and cementless knee replacements.
HOW WILL OUR RESEARCH HELP CLINICAL PRACTICE?
Our patient directed questions will help provide the first comprehensive answer of whether cement should or not be used overall and then for different replacement designs and patient groups. This will help provide more tailored patient care, potentially reduce repeat surgeries and improve knee surgery outcomes, whilst empowering patients to make more informed decisions. The results of this work will also help guide healthcare providers into which treatment is the most medically and cost-effective and therefore has potential to change practice globally.