Knee loading in OA subjects is correlated to flexion and adduction moments and to contact point locations

This study evaluated the association of contact point locations with the knee medial and lateral contact force (F-med, F-lat) alterations in OA and healthy subjects. A musculoskeletal model of the lower limb with subject-specific tibiofemoral contact point trajectories was used to estimate the F-med and F-lat in ten healthy and twelve OA subjects during treadmill gait. Regression analyses were performed to evaluate the correlation of the contact point locations, knee adduction moment (KAM), knee flexion moment (KFM), frontal plane alignment, and gait speed with the F-med and F-lat. Medial contact point locations in the medial-lateral direction showed a poor correlation with the F-med in OA (R-2=0.13, p=0.01) and healthy (R-2=0.24, p=0.001) subjects. Anterior-posterior location of the contact points also showed a poor correlation with the F-med of OA subjects (R-2=0.32, p<0.001). Across all subjects, KAM and KFM remained the best predictors of the F-med and F-lat, respectively (R-2 between 0.62 and 0.69). Results suggest different mechanisms of contact force distribution in OA joints. The variations in the location of the contact points participate partially to explains the F-med variations in OA subjects together with the KFM and KAM.

Automated summary

This study found that the location of contact points had little impact on knee medial and lateral contact force in OA patients and healthy subjects. The anterior-posterior position of the medial contact points had a weak correlation with medial contact force in OA patients. Knee adduction moment and knee flexion moment remained the best predictors of contact force.