Unicompartmental knee arthroplasty (UKA) offers significant advantages over total knee arthroplasty (TKA) but is reported to have higher revision rates in joint registries. In both the New Zealand and the UK national registry the revision rate of cementless UKR is less than cementless. It is not clear whether this is because the cementless is better or because more experienced surgeons, who tend to get better results are using cementless. We aim to use registry data to compare cemented and cementless UKA outcomes, matching for surgical experience and other factors. We performed a retrospective observational study using National Joint Registry (NJR) data on 10,836 propensity matched Oxford UKAs (5418 cemented and 5418 cementless) between 2004 and 2015. Logistic regression was utilized to calculate propensity scores to match the cemented and cementless groups for multiple confounders using a one to one ratio. Standardised mean differences were used before and after matching to assess for any covariate imbalances. The outcomes studied were implant survival, reasons for revision and patient survival. The endpoint for implant survival was revision surgery (any component removal or exchange). Cumulative patient and implant survival rates were determined using the Kaplan-Meier method. Patients not undergoing revision or death were censored on the study end date. The study endpoints implant and patient survival were compared between cemented and cementless groups using Cox regression models with a robust variance estimator.Introduction
Methods
Unicompartmental knee arthroplasty provides a good alternative to total knee arthroplasty in patients with isolated medial compartment osteoarthritis. There has been variable reporting in the literature as to whether age and sex affect the survival of unicompartmental knee arthroplasty. The aims of this study were to determine whether age and sex were predictors of failure for the Oxford unicompartmental knee arthroplasty.Background
Study aims
A number of studies have reported on the early failure of the Oxford unicompartmental knee arthroplasty. However, less evidence is available regarding the outcome following revision of failed unicompartmental knee prostheses to total knee arthroplasty. The study aims were to determine the time to failure and mode of failure for the Oxford unicompartmental knee arthroplasty and to assess the short-term outcome following revision surgery.Background
Study aims
