Does pre-operative anxiety and/or depression affect patient outcome after primary knee replacement arthroplasty?

Chronic pain is associated with psychological distress, most commonly manifested as anxiety and/or depression. In order to investigate the effect of such distress on outcome from knee arthroplasty, we prospectively investigated the anxiety and depression levels of 104 patients undergoing a total of 107 primary knee arthroplasty procedures and the outcomes they achieved pre-operatively and at six weeks, one year and seven years post-operatively. The Hospital Anxiety and Depression Scale was used to record psychological status. Oxford Knee Score and American Knee Society Score were used to record functional outcomes. Forty-four percent (47/107) of the patients had an abnormal pre-operative anxiety and/or depression score. Mean anxiety and depression scores improved at six weeks and one year of follow-up, but then deteriorated slightly at seven years, albeit not back to baseline. Knee scores showed similar patterns over time. Regardless of pre-operative psychological status, mean AKSS Knee scores improved at six weeks and further improved at one year post-op. They then showed slight deterioration at seven years, but remained significantly better than pre-op. Psychological distress is common in our patients pre-operatively. Improvements in knee pain and function as a result of surgery correlate well with lower levels of psychological distress post-operatively. Knee replacement surgery positively influences all of the outcome measures studied rather than recovery being negatively influenced by pre-operative states. Knee replacement arthroplasty is not contra-indicated by pre-operative psychological distress. Successful knee replacement improves knee pain and function, as well as symptoms of anxiety and depression. These improvements persist for many years after the surgery.