Patient-reported outcomes after total and unicompartmental knee arthroplasty: a study of 14,076 matched patients from the National Joint Registry for England and Wales.
Liddle AD., Pandit H., Judge A., Murray DW.
Whether to use total or unicompartmental knee replacement (TKA/UKA) for end-stage knee osteoarthritis remains controversial. Although UKA results in a faster recovery, lower rates of morbidity and mortality and fewer complications, the long-term revision rate is substantially higher than that for TKA. The effect of each intervention on patient-reported outcome remains unclear. The aim of this study was to determine whether six-month patient-reported outcome measures (PROMs) are better in patients after TKA or UKA, using data from a large national joint registry (NJR). We carried out a propensity score-matched cohort study which compared six-month PROMs after TKA and UKA in patients enrolled in the NJR for England and Wales, and the English national PROM collection programme. A total of 3519 UKA patients were matched to 10 557 TKAs. The mean six-month PROMs favoured UKA: the Oxford Knee Score was 37.7 (95% confidence interval (CI) 37.4 to 38.0) for UKA and 36.1 (95% CI 35.9 to 36.3) for TKA; the mean EuroQol EQ-5D index was 0.772 (95% CI 0.764 to 0.780) for UKA and 0.751 (95% CI 0.747 to 0.756) for TKA. UKA patients were more likely to achieve excellent results (odds ratio (OR) 1.59, 95% CI 1.47 to 1.72, p < 0.001) and to be highly satisfied (OR 1.27, 95% CI 1.17 to 1.39, p < 0.001), and were less likely to report complications than those who had undergone TKA. UKA gives better early patient-reported outcomes than TKA; these differences are most marked for the very best outcomes. Complications and readmission are more likely after TKA. Although the data presented reflect the short-term outcome, they suggest that the high revision rate for UKA may not be because of poorer clinical outcomes. These factors should inform decision-making in patients eligible for either procedure.