For FE models with EFD cartilage, the anterolateral region of the acetabulum had larger peak maximum shear stress and first principal strain than all other anatomical regions, consistent with observations of cartilage damage in disease. Models with neo-Hookean cartilage predicted smaller transchondral gradients of maximum shear stress than those with Veronda Westmann and EFD models. Conversely, the neo-Hookean model predicted the smallest peak stresses and largest peak strains. The EFD model had the stiffest response with increasing strains, predicting the largest peak stresses and smallest peak strains. Mesh convergence analysis demonstrated that five trilinear elements were adequate through the depth of the cartilage for precise predictions. Transchondral predictions of maximum shear stress and first principal strain were determined. Five specimen-specific FE models were evaluated using three constitutive models for articular cartilage: quasilinear neo-Hookean, nonlinear Veronda Westmann, and tension-compression nonlinear ellipsoidal fiber distribution (EFD). The objectives of this study were to use a population of validated finite element (FE) models of normal human hips to evaluate the required mesh for converged predictions of cartilage tensile strain and shear stress, to assess the sensitivity to cartilage constitutive assumptions, and to determine the patterns of transchondral stress and strain that occur during activities of daily living. This damage may be caused by elevated first principal (most tensile) strain and maximum shear stress.

Cartilage fissures, surface fibrillation, and delamination represent early signs of hip osteoarthritis (OA).

Febio postview plot function of depth