Preoperative stiffness is the most important predictor of postoperative patient's satisfaction after total knee arthroplasty.

PURPOSE: To predict the most important preoperative factor affecting the patient satisfaction after total knee arthroplasty (TKA) in trial to improve patient counselling process.

METHODS: We retrospectively reviewed all patients who underwent primary TKA from January 1, 2018, to January 31, 2019, with minimum one-year follow-up for the previously collected patient-reported outcome measures (PROMs) as Oxford Knee Score (OKS) and Knee Injury and Osteoarthritis Outcome Score for joint replacement (KOOS, JR) preoperative, 6 months and 12 months postoperative.

RESULTS: By using Oxford knee score at 12 months as dependent variable, we found a negative moderate spearman correlation between age and Oxford knee score at 12 months postoperative. Moderate negative spearman correlation was also found between Oxford knee score at 12 months postoperative and KOOS pain, stiffness and function scores at preoperative and 6 months postoperative, denoting higher satisfaction at 12 months with less perceived stiffness, pain and limited function at baseline and 6 months postoperative. A multivariate regression analysis was done using the oxford knee score at 12 months as dependent variable to detect the predictors of oxford knee score at 12 months postoperatively and showed that younger age and less perception of stiffness at baseline were significant predictors of higher Oxford knee score: higher satisfaction at 12 months postoperative.

CONCLUSION: Preoperative stiffness can predict the postoperative satisfaction score more than any other factor. We also address the importance of combining more than one PROM in assessing patients as OKS and KOOS, JR.