Optimism and pessimism are antithetically associated with post-operative knee function in patients’ undergoing total knee arthroplasty

PURPOSE: Personality traits, such as dispositional optimism and pessimism, have impact on a variety of health-related problems. Influence on outcome in total knee arthroplasty (TKA) could only be shown for other personality trait concepts, but not for dispositional optimism/pessimism. This study aims to examine the association of dispositional optimism/pessimism with pre-operative joint function and post-operative outcome in TKA. METHODS: Data were acquired in a multicentre, cross-sectoral, prospective study (the PROMISE Trial). Patients were followed for 12 months post-operatively. Dispositional optimism/pessimism was measured pre-operatively via the revised Life Orientation Test (LOT-R), pre- and post-operative function was measured via the 12 Item Knee-osteoarthritis outcome Scores (KOOS-12). Log-linear regression models considering known confounders and t-test were carried out to show the association of LOT-R scores with pre- and post-operative KOOS-12 scores. RESULTS: 740 patients were analyzed. Optimistic LOT-R was significantly positively associated to the mean scores of KOOS-12 pre- and post-operative, while pessimistic LOT-R was significantly associated negatively (pre-operative: optimistic p = 0.001, pessimistic p = 0.001; post-operative optimistic: 3M p = 0.001, 6M p = 0.001, 12M p = 0.001; post-operative pessimistic: 3M p = 0.01, 6M p = 0.004, 12M p = 0.001). CONCLUSION: Optimism was positively associated with pre-operative joint function and, more importantly, post-operative functional outcome in TKA, while pessimism was associated with the opposite. Assessing patients’ general personality traits prior to surgery to identify pessimistic patients, hence being at risk for poor outcome in TKA, should be considered to react to the patients’ special needs and possible pessimistic expectations, i.e., through a cognitive–behavioral intervention, to potentially increase optimism and hereby post-operative outcome in TKA. LEVEL OF EVIDENCE: Prognostic Level III.