Relationships Between Running Biomechanics and Femoral Articular Cartilage Thickness and Composition in Anterior Cruciate Ligament Reconstruction Patients

Abstract

ABSTRACTBackgroundAlthough individuals with anterior cruciate ligament reconstruction (ACLR) are at high risk for posttraumatic osteoarthritis, mechanisms underlying the relationship between running and knee cartilage health remain unclear.ObjectiveWe aimed to investigate how 30 min of running influences femoral cartilage thickness and composition and their relationships with running biomechanics in patients with ACLR and controls.MethodsTwenty patients with ACLR (time post‐ACLR: 14.6 ± 6.1 months) and 20 matched controls participated in the study. A running session required both groups to run for 30 min at a self‐selected speed. Before and after running, we measured femoral cartilage thickness via ultrasound imaging. A MRI session consisted of T2 mapping.ResultsThe ACLR group showed longer T2 relaxation times in the medial femoral condyle at resting compared with the control group (central: 51.2 ± 16.6 vs. 34.9 ± 13.2 ms, p = 0.006; posterior: 50.2 ± 10.1 vs. 39.8 ± 7.4 ms, p = 0.006). Following the run, the ACLR group showed greater deformation in the medial femoral cartilage than the control group (0.03 ± 0.01 vs. 0.01 ± 0.01 cm, p = 0.001). Additionally, the ACLR group showed significant negative correlations between resting T2 relaxation time in the medial femoral condyle and vertical impulse (standardized regression coefficients = −0.99 and p = 0.004) during running.ConclusionsOur findings suggest that those who are between 6 and 24 months post‐ACLR have degraded cartilage composition and their cartilage deforms more due to running vGRF.