Aims: To establish whether pre-existing anxiety and depression negatively impacts symptomatic and functional outcome of knee arthroplasty.

Methodology: A prospective study. Ethical approval was obtained prior to the study. Psychological status was assessed using the Hospital Anxiety and Depression Scale; a validated self-assessment tool for detecting anxiety and depression. The Oxford and the American Knee society scores were used to assess the knee status. All scores were documented pre-operatively and at six weeks post-operatively. Results were submitted for independent statistical analysis.

Results: 105 consecutive primary knee replacements were included in the study. 39% (41 patients) had abnormal pre-operative anxiety states. This percentage dropped to 28.2% (29 patients) post-operatively (P=0.034). 25.7% (27 patients) had abnormal pre-operative depression states which improved to 15.5% (16 patients) post-operatively (P=0.011). There were high degrees of correlation between abnormal anxiety and depression states both pre-operatively (P< 0.001) and post-operatively (P< 0.001). Patients with abnormal anxiety pre-operatively had worse knee scores both pre-operatively (P=0.17) and post-operatively (P=0.009) than those who did not. Patients with abnormal depression pre-operatively had worse pre-operative Oxford scores (P=0.036), and worse Oxford (p=0.006) and AKSS knee scores post-operatively (0.043).

Conclusions: Abnormal anxiety and depression states are common in patients with knee arthritis presenting for knee arthroplasty. These conditions can improve post-operatively. Patients with abnormal pre-operative anxiety and depression do less well following knee arthroplasty than those who do not. Pre-operative psychological assessment is easy to perform and does act as a predictor of early outcome. Further research is needed to assess whether treating these psychological conditions prior to knee arthroplasty improves the outcome or not.