Associations between mechanical loading and femoral cartilage deformation in healthy individuals

Undergraduates: Gabrielle Smith, Matthew Harkey

Faculty Advisor: Brian Pietrosimone
Department: Exercise & Sport Science

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Osteoarthritis is preceded by subclinical alterations in articular cartilage. Joint biomechanics are associated with changes in cartilage thickness and could predict risk for OA development. This study determined the associations between acute femoral cartilage deformation in the medial, lateral, and intercondylar compartments of the knee and peak vertical ground reaction force (vGRF) and instantaneous vGRF loading rate during walking in healthy individuals. Femoral cartilage thickness in the three compartments was measured with ultrasound before and after the walking protocol. Cartilage deformation was calculated as the percent change between the two measurements. Five walking gait trials were recorded in a motion capture laboratory to assess biomechanical variables. Participants walked for 5000 steps on a treadmill. Pearson product-moment correlations evaluated the associations between biomechanical and ultrasound variables. Instantaneous vGRF loading rate was significantly positively associated with lateral femoral cartilage deformation (r=0.335, P=0.039, n=38), indicating that less cartilage deformation associated with a higher loading rate. No significant associations were found between other measures. Lateral condyle deformation was more associated with rate of loading than magnitude of loading during walking. The lack of associations between other variables indicates that loading may differentially affect other portions of the femoral surface.