The role of presurgical expectancies in predicting pain and function one year following total knee arthroplasty

The present study examined the prospective value of response expectancies (ie, pain, sleep) and behavioral outcome expectancies (ie, return to function) in the prediction of pain severity and functional limitations 12 months after total knee arthroplasty (TKA). The study sample consisted of 120 individuals (73 women, 47 men) with osteoarthritis of the knee who were scheduled for TKA. Measures of expectancies, pain severity, pain catastrophizing, pain-related fears of movement, and depression were completed prior to surgery. Participants also completed measures of pain severity and functional limitations 12 months following surgery. Analyses revealed that behavioral outcome expectancies were stronger predictors of follow-up pain and functional limitations than response expectancies. Consistent with previous research, analyses also revealed that pain catastrophizing, pain-related fear of movement, and depression predicted follow-up pain and function. In a multivariate analysis, only pain catastrophizing contributed significant unique variance to the prediction of follow-up pain and function. Behavioral outcome expectancies partially mediated the relation between catastrophizing and follow-up pain and function. The relation between catastrophizing and follow-up pain severity and functional limitations remained significant even when controlling for behavioral outcome expectancies. The results suggest that interventions designed to specifically target behavioral outcome expectancies and catastrophizing might improve post-surgical outcomes.