Objective To test the hypothesis that knee cartilage changes over five years are associated with baseline peak knee adduction moment (KAM) and peak knee flexion moment (KFM) during early stance. Design Baseline KAM and KFM were measured in sixteen subjects with medial knee OA. Regional changes in cartilage thickness and changes in medial-to-lateral thickness ratio were quantified using magnetic resonance imaging at baseline and again after five years. Multiple regression was used to determine whether baseline measures of KAM and KFM were associated with cartilage changes over five years. Associations with baseline pain score, Kellgren-Lawrence grade, walking speed, age, gender, and body mass index were tested one-by-one in the presence of KAM and KFM. Results Changes over five years in femoral medial-to-lateral thickness ratio were associated with baseline KAM, KFM, and pain score (R2=0.60, p=0.010), and most significantly with KAM (R2=0.33, p=0.019). Changes in tibial medial-to-lateral thickness ratio were associated with baseline KAM, KFM, and walking speed (R2=0.49, p=0.039), with KFM driving this association (R2=0.40, p=0.009). Changes in medial tibial thickness were associated with baseline KAM, KFM, and walking speed (R2=0.49, p=0.041); KFM also drove this association (R2=0.42, p=0.006). Conclusions The findings that the KAM has a greater influence on femoral cartilage change and the KFM has a greater influence on tibial cartilage change provide new insight into the tibiofemoral variations in cartilage changes associated with walking kinetics. These results suggest that both KAM and KFM should be considered when designing disease interventions as well as when assessing the risk for OA progression.

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Elevated deep UTE-T2* values of medial knee cartilage 2 years after ACLR correlate with 2 clinical markers of increased risk of medial knee OA. These results support the clinical utility of MRI UTE-T2* for early diagnosis of subsurface cartilage abnormalities. Longitudinal follow-up of larger cohorts is needed to determine the predictive and staging potential of UTE-T2* for posttraumatic OA.