Early post-operative oxford knee score and knee society score predict patient satisfaction 2 years after total knee arthroplasty.

Abstract

There is poor correlation between functional outcomes and patient satisfaction following total knee arthroplasty (TKA). We asked if early post-operative scores at 6months or the pre- to post-operative change in scores are predictive of patient satisfaction 2years after TKA. We conducted a retrospective review of prospectively collected registry data of 4359 TKAs performed at a single institution. At 6months and 2years, the Knee Society Score (KSS), Oxford Knee Score (OKS), and Short-Form 36 scores were assessed. A satisfaction questionnaire was alsocompleted. Logistic regression was used to generate receiver-operating characteristic (ROC) curves to assess the ability of each scoring system in predicting satisfaction at 2years. At 2years, 91.1% of patients were satisfied. For the absolute post-operative OKS at 6months, an AUC of 0.762 (95% CI 0.736-0.788) and a threshold of ≤ 21.5 points (or ≥38.5 points on the new scale)were obtained. For the KSS knee score, an AUC of 0.704 (95% CI 0.674-0.734) and a threshold of ≥ 80.5 points were identified. The OKS performed significantly better than the KSS knee score (p = 0.03) and the other post-operative scores (p < 0.001). When analysing the change in scores pre-operatively to 6months, the AUC was < 0.7 for all scales. Early post-operative scores, specifically the OKS and KSS knee score, can predict patient satisfaction at 2years after TKA with good accuracy. The threshold values offer surgeons an additional tool to identify patients at risk of dissatisfaction at 2years, enabling them to intervene earlier to ensure good patient satisfaction. III, retrospective cohort study.