Changes in Anxiety and Depression Are Mediated by Changes in Pain Severity in Patients Undergoing Lower-Extremity Total Joint Arthroplasty

Background: Depression and anxiety are common comorbidities in chronic pain including osteoarthritis patients undergoing total joint arthroplasty (TJA). What is not clear is whether psychiatric comorbidity precedes the manifestation of painful states or represents a reaction to living with chronic pain and associated functional impairment. The objective of this research was to explore whether decreases in depressive and anxiety symptoms after lower-extremity TJA could be due to postsurgical reductions in pain. Methods: We conducted a secondary analysis of data from 1448 TJA patients enrolled in the Analgesics Outcome Study. Patients completed measures of pain intensity, functional status, and depressive and anxiety symptoms preoperatively and at 3 and 6 months postoperatively. Data were analyzed using a structural equation modeling approach. Results: We found that improvement in pain and physical function from baseline to 6 months postoperatively was associated with improvement in depression and anxiety symptoms. We also found that a change in overall body pain at 3 months after surgery significantly mediated changes in both the depression and anxiety scores at 6 months after surgery even when controlling for age, sex, baseline body pain, education, opioid use, and type of surgery. Conclusions: Presurgical affective symptoms not only have an effect on change in postsurgical pain, whereby lower preoperative scores on depression and anxiety were associated with lower postsurgical pain, but also postsurgical decreases in pain were associated with lower levels of depression and anxiety after surgery. Taking these points into consideration may prove useful in working toward better outcomes for TJA.