Longitudinal Changes in Psychosocial Factors and Their Association With Knee Pain and Function After Anterior Cruciate Ligament Reconstruction

Background. Evidence in the musculoskeletal rehabilitation literature suggests that psychosocial factors can influence pain levels and functional outcome. Objective. The purpose of this study was to examine changes in select psychosocial factors and their association with knee pain and function over 12 weeks after anterior cruciate ligament (ACL) reconstruction. Design. This was a prospective, longitudinal, observational study. Methods. Patients with ACL reconstruction completed self-report questionnaires for average knee pain intensity (numeric rating scale [NRS]), knee function (International Knee Documentation Committee Subjective Knee Form [IKDC-SKF]), and psychosocial factors (pain catastrophizing [Pain Catastrophizing Scale], fear of movement or reinjury [shortened version of the Tampa Scale for Kinesiophobia (TSK-11)], and self-efficacy for rehabilitation tasks [modified Self-Efficacy for Rehabilitation Outcome Scale (SER)]). Data were collected at 4 time points after surgery (baseline and 4, 8, and 12 weeks). Repeated-measures analyses of variance determined changes in questionnaire scores across time. Hierarchical linear regression models were used to examine the association of psychosocial factors with knee pain and function. Results. Seventy-seven participants completed the study. All questionnaire scores changed across 12 weeks. Baseline psychosocial factors did not predict the 12-week NRS or IKDC-SKF score. The 12-week change in modified SER score predicted the 12-week change in NRS score (r(2) = .061), and the 12-week change in modified SER and TSK-11 scores predicted the 12-week change in IKDC-SKF score (r(2) = .120). Limitations. The psychometric properties of the psychosocial factor questionnaires are unknown in people with ACL reconstruction. The study focused on short-term outcomes using only self-report measures. Conclusions. Psychosocial factors are potentially modifiable early after ACL reconstruction. Baseline psychosocial factor levels did not predict knee pain or function 12 weeks postoperatively. Interventions that increase self-efficacy for rehabilitation tasks or decrease fear of movement or reinjury may have potential to improve short-term outcomes for knee pain and function.