This project is an interdisciplinary effort on the study of diarthrodial joint biomechanics utilizing automated and adaptive nonlinear three-dimensional finite element analysis (FEA) to describe the actual anatomic geometries and biphasic properties of articular cartilage on the joint surface. Significant recent advances have been made in the development of: 1) mixture constitutive equations to describe the behaviors of hydrated soft tissues; 2) finite element formulations for these mixture equations; 3) the boundary conditions between the synovial fluid and the articular surface; and 4) the determination of three-dimensional anatomic geometry of joints. What is now required is a comprehensive undertaking for the development of computational mechanics methods leading to an automated and adaptive finite element numerical model for the deformational response of diarthrodial joints. Thus the fundamental studies will focus on the development of the 1) FEA of three-dimensional problems utilizing the nonlinear finite deformation biphasic laws for articular cartilage; 2) automated and adaptive methods for the generation of two-dimensional and three-dimensional meshes required for the FEA to account for known singular boundary layer effects; and 3) interface for the ditigal stereophotogrammetric (SPG) anatomic data with the automatic mesh generation in our 3-D FEA meshes. These studies will provide significant advances toward a precise 3-D simulation of biomechanical problems related to diarthrodial joints, with realistic loading conditions, joint geometries, loads, and constituent material properties. Ultimately, these fundamental studies can provide an understanding of the complex biomechanical behaviors of normal and pathological human joints, as well as the possibility of the development of new interactive computer programs for imaging and diagnostic techniques to develop new clinical treatment modalities.
