Effect of functional knee loading on articular cartilage MRI T2 relaxation time and thickness in patients at risk for knee osteoarthritis

Abstract

ObjectivesThe objectives of this study were: 1) to evaluate the effect of a functional loading stimulus on MRI-acquired T2 relaxation time (T2) and thickness of knee articular cartilage, and 2) to compare the response between patients at risk for knee OA and healthy controls. DesignA total of 32 participants (16 healthy controls [24.7 ± 3.0 years], and 16 at-risk participants [37.5 ± 12.2]) underwent 3T MRI T2 mapping scans immediately before and after a standardized 25-minute functional loading stimulus on a computerized treadmill that included a variety of challenging walking conditions. Groups were defined using the Osteoarthritis Initiative Control (healthy) and Incidence Cohort (at-risk) Criteria. We analyzed changes in T2 between groups in the superficial and deep layers of tibiofemoral, patellar, and trochlear cartilage, and for tibiofemoral cartilage thickness using multivariate linear mixed-effects models. ResultsT2 was shorter in the superficial cartilage layers in both groups. The mean combined change (95 % confidence interval) in T2 of the superficial layer was -3.80 ms (-4.87; -2.73) for at-risk participants and -3.89 ms (-4.96; -2.82) for healthy controls. The between-group difference in change was 0.09 ms (-1.04; 1.22). There was a decrease in articular cartilage thickness in the lateral compartment for healthy controls (-0.14 mm [-0.24; -0.04]), otherwise there were no changes detected. ConclusionsConsistently shorter T2 was observed in the articular cartilage of patients at risk for knee OA and in healthy controls, after a challenging walking test, but with no concurrent change in cartilage thickness, suggesting a similar articular cartilage response to functional loading.