An Enhanced Discrete Element Model for Predicting Hip Contact Stresses

Chronic exposure to excessive stress on articular cartilage in the hip joint predicts the progression and onset of osteoarthritis (OA) [1]. Discrete element analysis (DEA) has been used to predict cartilage contact stresses [2, 3]. Because of its low computational expense and relative ease of application, DEA could be an effective alternative to the finite element (FE) method for the study of contact stresses in the hip. Previous DEA models have assumed concentric hip joint geometry and constant cartilage thickness. These assumptions lead to underestimates for cartilage contact stress and predict unrealistic, simplified contact patterns [2, 4]. It is possible that DEA could provide more realistic predictions of cartilage contact stress if subject-specific bone and cartilage geometry were used. The objectives of this study were to develop a DEA model that accommodates subject-specific bone and cartilage geometry, and to compare DEA model predictions of cartilage contact stresses with predictions from validated FE models.