The Cardiff Arthroplasty Satisfaction Index (CASI). A simple tool for the assessment of outcome following knee arthroplasty.

Our aim was to develop a patient reported outcome measure of satisfaction following total knee arthroplasty (TKA) and assess its correlation with Oxford knee score (OKS), Quality of life (EQ5D) and Visual analogue scale for pain (VAS). 172 patients with minimum 5year follow up post primary total knee arthroplasty completed CASI, OKS, EQ5D and VAS for pain. Receiver-operator curve analysis was performed to identify an OKS threshold of poor satisfaction defined by CASI rarely/never. The CASI showed positive correlation with the OKS, VAS for pain, and EQ5D, (Spearman's rho); 0.779; 0.711; 0.629. A threshold of 20 for the Oxford Knee score had 85% specificity and 85% sensitivity for poor satisfaction on CASI. The CASI is a useful measure of patient satisfaction following TKA.