Does increasing applied load lead to contact changes indicative of knee osteoarthritis? A subject-specific FEA study

Summary This study investigated whether increased loading (representing obesity) in the extended knee and flexed knee led to increased stresses in areas of typical medial and lateral osteoarthritis cartilage lesions, respectively. We created two paired sets of subject‐specific finite element models; both sets included models of extended knees and of flexed knees. The first set represented normal loading; the second set represented increased loading. All other variables were held constant. The von Mises stresses and contact areas calculated on the tibial cartilage surfaces of the paired models were then compared. In the extended knee models, applying a larger load led to increased stress in the anterior and central regions of the medial tibial cartilage. These are the typical locations of medial osteoarthritis cartilage lesions. Therefore, the results support that increased loading in the extended knee may result in medial osteoarthritis. In the flexed knee models, applying a larger load increased stress in the anterior and central regions of the lateral tibial cartilage. Lateral osteoarthritis cartilage lesions typically occur centrally and posteriorly. Therefore, these results do not support our hypothesis. Shear stress was increased in areas of typical lateral lesions, however, and should be investigated in future studies. Copyright © 2015 John Wiley & Sons, Ltd. Obesity has been linked to osteoarthritis initiation, with loading during extension and flexion suggested to result in unicompartmental medial and lateral osteoarthritis, respectively. We created two sets of computational models: one set with a normal load and one set with an increased load. For both extended and flexed knees, applying larger loads resulted in elevated stresses in the anterior and central regions of the tibial cartilage; these areas of higher stresses matched typical medial (but not lateral) osteoarthritis lesion locations.