The role of preoperative self-efficacy in predicting outcome after total knee replacement.

OBJECTIVES: The aim of the present study was to determine if self-efficacy is a significant and independent preoperative predictor of patient-reported pain and function at one year after total knee replacement (TKR).
METHODS: Patients listed for a primary TKR because of osteoarthritis were recruited from preoperative assessment clinics at one regional orthopaedic centre. Before surgery, patients completed the Western Ontario and McMasters Osteoarthritis Index (WOMAC) Pain and Function Scale, Pain Self-Efficacy Scale, the Hospital Anxiety and Depression Scale, the Self-Administered Co-morbidity Questionnaire and questions about other painful joints. Patients then completed the WOMAC Pain and Function Scales at one year postoperatively. Regression analysis was performed to determine if self-efficacy was a significant predictor of outcome after TKR.
RESULTS: Overall, 251 patients were recruited into this study, and one-year questionnaire data were available for 220 patients. At one year postoperatively, 7% of patients reported severe pain in their replaced knee and 9% reported severe functional limitations. Self-efficacy was found to be a significant preoperative predictor of functional ability, but not pain, at one year postoperatively, after controlling for age, gender, depression, anxiety, number of medical co-morbidities, preoperative knee status and painful joints elsewhere. Significant predictors of postoperative pain were greater anxiety and higher pain severity. Other significant predictors of postoperative disability were greater anxiety, worse functional disability and a greater number of painful joints elsewhere.
CONCLUSIONS: The present study demonstrated that self-efficacy is a significant preoperative predictor of patient-reported functional ability at one year after TKR. Future research is needed to assess the impact of interventions for enhancing self-efficacy on patient-reported outcomes after TKR.