Association of Self-Reported Anxiety and Depression Symptoms with Knee Pain Severity in Individuals with Anterior Cruciate Ligament Reconstruction

Background: Psychological responses to injury are common after anterior cruciate ligament (ACL) injury and reconstruction (ACLR) and have been linked to knee-related pain during early recovery. However, it remains unknown whether anxiety and depression symptoms are associated with knee pain severity at later stages of recovery, when unresolved or recurrent psychological distress may persist. Purpose/Hypothesis: The purpose of this study was to examine the association of anxiety and depression symptoms with knee pain severity in individuals 3 to 12 months after ACLR. It was hypothesized that individuals who exhibited more severe anxiety and depression symptoms would report more knee pain. Study Design: Cross-sectional study; Level of evidence, 3. Methods: In total, 131 individuals who were 3 to 12 months after primary, unilateral ACLR (time since ACLR = 5.7 ± 1.7 months; age = 18.3 ± 2.1 years; 37.4% male) were included. Anxiety and depression symptoms were measured with the Patient-Reported Outcomes Measurement Information System Anxiety and Depression 4-item short forms, respectively, where higher scores reflect more severe symptoms. Knee pain was measured with the Knee injury and Osteoarthritis Outcome Score Pain subscale, where higher scores indicate less or no knee pain. Separate multiple hierarchical regression analyses were conducted to examine the association of self-reported anxiety and depression symptoms with knee pain severity. Sex, age, and time since ACLR were entered in step 1 of each model. Anxiety and depression symptom scores were entered in step 2 of their respective models, and the change in R 2 was examined. Results: Sex, age, and time since ACLR explained 3% of the variance in knee pain severity ( R 2 = 0.031, P = .23). Anxiety symptoms accounted for an additional 25.7% of the variance in knee pain severity (Δ R 2 = 0.257, P < .001), while depression symptoms accounted for an additional 15.7% of the variance in knee pain severity (Δ R 2 = 0.157, P < .001). Conclusion: Self-reported anxiety and depression symptoms were significantly associated with knee pain severity in individuals 3 to 12 months after ACLR. These findings support assessment of anxiety, depression, and knee pain, even in the later phases of ACLR rehabilitation, to help inform clinical decision-making.