Psychological determinants of problematic outcomes following Total Knee Arthroplasty.

The primary objective of the present study was to examine the role of pain-related psychological factors in predicting pain and disability following Total Knee Arthroplasty (TKA). The study sample consisted of 75 (46 women, 29 men) individuals with osteoarthritis of the knee who were scheduled for TKA. Measures of pain severity, pain catastrophizing, depression, and pain-related fears of movement were completed prior to surgery. Participants completed measures of pain severity and self-reported disability 6 weeks following surgery. Consistent with previous research, cross-sectional analyses revealed significant correlations among measures of pre-surgical pain severity, pain catastrophizing, depression and pain-related fears of movement. Prospective analyses revealed that pre-surgical pain severity and pain catastrophizing were unique predictors of post-surgical pain severity (6-week follow-up). Pain-related fears of movement were predictors of post-surgical functional difficulties in univariate analyses, but not when controlling for pre-surgical co-morbidities (e.g. back pain). The results of this study add to a growing literature highlighting the prognostic value of psychological variables in the prediction of post-surgical health outcomes. The results support the view that the psychological determinants of post-surgical pain severity differ from the psychological determinants of post-surgical disability. The results suggest that interventions designed to specifically target pain-related psychological risk factors might improve post-surgical outcomes.