Biomechanical Factors Associated With Pain and Symptoms Following Anterior Cruciate Ligament Injury and Reconstruction

Background Few studies have investigated the associations between patient-reported outcome and gait in patients with anterior cruciate ligament (ACL) injury and reconstruction over time. Because there is an association between ACL rupture and the presence of osteoarthritis later in life, a better understanding of these relationships will help to elucidate how patients’ gait pattern may affect pain and symptoms, potentially leading to better treatment for or preventing the development of knee OA. Objective To evaluate the associations between gait characteristics and self-reported pain and symptoms before, 6 months after, and 1 year after anterior cruciate ligament reconstruction. Design Prospective cohort study. Setting The Human Performance Center at the Orthopedic Institute at the University of California, San Francisco. Patients Patients with full unilateral ACL tears were enrolled. A total of 43 patients were included at 12 months postsurgery. Methods The independent variable in this study comprised specific gait variables in patients who had undergone ACL reconstruction. At each time point, 3-dimensional motion analysis was performed. Participants also completed the Knee Osteoarthritis Outcome Score (KOOS) questionnaire. Main Outcomes Measurements The primary study outcome measurement was the KOOS and was planned before data collection began. Partial correlations were used to examine cross-sectional associations between gait characteristics and KOOS pain and symptom scores at all time points. In addition, partial correlations were performed to examine the associations between change in postoperative KOOS from 6 months to 1 year and gait characteristics at baseline and 6 months. Results Significant associations between KOOS and gait characteristics were found at all time points, including an association between peak medial ground reaction force and pain (r = −0.344, P = .02) and symptoms (r = −0.407, P = .007) at baseline. Conclusions Specific gait variables may be predictive of greater pain and symptoms and less improvement over time postreconstruction. This could help to inform rehabilitation exercises post injury and pre reconstruction. Level of Evidence IV