How long do revised and multiply revised knee replacements last? An analysis of the National Joint Registry.

ABSTRACT

BACKGROUND: Knee replacements are common and effective operations but patients that undergo this intervention are at risk of needing subsequent costly and often complex revision surgery with poorer outcomes than primary surgery. The treatment pathway over the life of the patient in terms of risk of revision and re-revision(s) is poorly described. We aim to provide detailed information on the longevity of revision surgery. METHODS: This was a retrospective observational registry-based study of the National Joint Registry. Kaplan-Meier estimates were used to determine the cumulative probability of revision and subsequent re-revision(s) following primary knee replacement. Analyses were stratified by age and gender and the influence of time from first to second revision on the risk of further revision was explored. FINDINGS: There were 33,292 revision knee replacements with a linked primary episode. Revision rates of revision knee replacements were higher in males and younger patients. 19·9% of revisions were revised again within 13 years, 20·7% of second revisions were revised again within 5 years and 20·7% of third revisions were revised again within 3 years. A shorter time between revision episodes was associated with earlier subsequent revision. INTERPRETATION: Males and younger patients are at higher risk of multiple revisions. Patients who undergo a revision have steadily increasing risk of further revision the more procedures they undergo, and each subsequent revision lasts for approximately half the time of the previous one. FUNDING: This study was supported by the NIHR Biomedical Research Centre at University Hospitals Bristol and Weston National Health Service Foundation Trust and the University of Bristol. The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. This study was also supported by funding from Healthcare Quality Improvement Partnership and the National Joint Registry. Posts of authors of this work are part funded by a grant from the National Joint Registry to conduct statistical analysis for the National Joint Registry. AS was funded by a Medical Research Council Strategic Skills Fellowship MR/L01226X/1.