Quadriceps strength affects patient satisfaction after total knee arthroplasty

Background: Total knee arthroplasty is one of the most successful surgeries with respect to relieving pain and restoring function of the knee. However, some studies have reported that patients are not always satisfied with their results after total knee arthroplasty. The aim of this study was to determine whether the muscle strength around the knee joint and the walking status influence patients' expectations and satisfaction before and after total knee arthroplasty. Methods: We evaluated 28 patients who underwent 30 primary total knee arthroplasties from March 2012 to June 2013. We assessed patient-reported scores using the 2011 Knee Society Scoring System, knee extensor and flexor strength, the 10-m walking test, and the timed up-and-go test. All assessments were performed preoperatively and 1 year after total knee arthroplasty. We determined the correlation between the patient-reported scores and each variable. Results: Preoperative patient satisfaction was significantly correlated with knee symptoms and functional activities, but not with muscle strength or walking status. Postoperative patient satisfaction was significantly correlated with knee symptoms, functional activities, knee extensor strength, and walking status, including the 10-m walking test and timed up-and-go test, after total knee arthroplasty. In stepwise regression analysis, predictors of patient satisfaction with total knee arthroplasty were knee symptoms, functional ability, and knee extensor strength. Conclusions: Our study demonstrates that pain relief and restoration of functional activity are highly correlated with increasing patient satisfaction after total knee arthroplasty. The results also indicate that the quadriceps is important for patient satisfaction and restoration of functional activity following total knee arthroplasty. (C) 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.