THE EFFECT OF THE FRONTAL PLANE TIBIOFEMORAL ANGLE ON THE STRESS AND STRAIN AT THE KNEE CARTILAGE DURING THE STANCE PHASE OF THE GAIT CYCLE

Three-dimensional (3-D) finite element analysis (FEA) knee models were created to determine the effect of the frontal plane tibiofemoral angle on the stress and strain at the knee cartilage during the stance phase of the gait cycle. Knee models of three healthy subjects of different tibiofemoral angles and weight were created from sagittal view magnetic resonance images (MRI) of the knee. The loading conditions were determined from motion analysis and force platform data and a muscle force reduction model. During the stance phase, the subjects exhibited a valgus-varus-valgus knee moment pattern that determined the location and magnitude of the maximum stress and strain in the cartilage on the lateral or medial compartment of the knee. The highest values of the normal stress, Tresca shear stress and normal strain for each subject occurred at 25% of the stance phase of the gait cycle, where the maximum compressive load and varus knee moment occurred. The individual with the varus aligned knee had the largest stress and strain at the medial compartment of the knee compared to the normal aligned and valgus aligned individuals due to the larger varus knee moment exhibited during the stance phase of the gait cycle in the varus aligned individual. The results from the FEA data may be used by health care professional to identify individuals most susceptible to knee osteoarthritis (OA) and assist in developing preventive measure to slow and possibly stop the initiation and progression of OA.