Abstract

Cartilage transmits and redistributes biomechanical loads in the knee joint during exercise. Exercise-induced loading alters cartilage hydration and is detectable using quantitative MRI, where T2 relaxation time (T2 ) is influenced by cartilage collagen composition, fiber orientation, and changes in extracellular matrix. This study characterized short-term transient responses of healthy knee cartilage to running-induced loading using bilateral scans and image registration. Eleven healthy female recreational runners (33.73±4.22 years) and four healthy female controls (27.25±1.38 years) were scanned on a 3T GE MRI scanner with qDESS before running over-ground (runner group) or resting (control group) for 40 minutes. Subjects were scanned immediately post-activity at five-minute intervals for 60 minutes. T2 times were calculated for femoral, tibial, and patellar cartilage at each time point and analyzed using a mixed-effects model and Bonferroni post-hoc. There were immediate decreases in T2 (mean±SEM) post-run in superficial femoral cartilage of at least 3.3±0.3% (P=0.002) between baseline and Time 0 that remained for 25 minutes, a decrease in superficial tibial cartilage T2 of 2.9±0.4% (P=0.041) between baseline and Time 0, and a decrease in superficial patellar cartilage T2 of 3.6±0.3% (P=0.020) 15 minutes post-run. There were decreases in the medial posterior region of superficial femoral cartilage T2 of at least 5.3±0.2% (P=0.022) within five minutes post-run that remained at 60 minutes post-run. Clinical Significance: These results increase understanding of transient responses of healthy cartilage to repetitive, exercise-induced loading and establish preliminary recommendations for future definitive studies of cartilage response to running. This article is protected by copyright. All rights reserved.

View details for DOI 10.1002/jor.24994

View details for PubMedID 33483997