Greater pre-operative anxiety, pain and poorer function predict a worse outcome of a total knee arthroplasty

Purpose Around 10–30 % of patients are dissatisfied with the results of their total knee arthroplasty (TKA). This review aimed to identify and evaluate the predictors of outcome measured by the three domains of health-related quality of life (pain, stiffness and function). The focus was on pre-operative psychological factors as related to other patient-related variables. Methods A systematic search was performed using the following databases: MEDLINE, PubMed, AMED, CINAHL, PsychINFO, SciFinder, Scopus, EMBASE, Cochrane, Lilacs, Web of Science and ScienceDirect. The quality of identified studies was assessed using the Critical Appraisal Skills Programme Cohort checklist. Results Ten studies met the eligibility criteria. From these, nine patient-related predictors of outcome were identified (depression, anxiety, age at surgery, gender (being female), medical co-morbidities, BMI, level of education, pre-operative pain severity and pre-operative knee function). Greater anxiety, pre-operative pain and function were the most significant factors to predict a poorer outcome of a TKA. The results of depression, gender (female), medical co-morbidities, BMI and level of education were variable among the included studies. There was very little evidence to support older age at operation as a predictor of poorer outcome. Conclusion Patients experiencing high levels of pain before surgery should be informed of the chances of improvement by having a TKA. A validated psychological screening tool that separates depression and anxiety is recommended as part of the pre-operative assessment stage. Patients presenting with symptoms of depression and anxiety should be identified and consulted before a TKA. Level of evidence II.