A Physically Based Model to Simulate Orthopedic Surgery from 3D CT Image

The objective of this paper is to describe strategies for a physically based model to simulate setting bone surgery from 3D CT image with the finite element (FE) method. A patient´s leg sample was selected and scanned by CT at the direction parallel to the Frankfort Horizontal plane. A three-dimensional (3D) finite element model of the human leg was developed using the actual geometry of the leg skeleton and soft tissues, which were obtained from 3D reconstruction of CT images. All joints were defined as contact surfaces, which allow relative articulating movement. The major ligaments were simulated using tension-only truss elements by connecting the corresponding attachment points on the bone surfaces. The bony and ligamentous structures were embedded in a volume of soft tissues. The muscles were defined as non-linear material, and the skin, ligaments and tendons were defined as hyperelastic, while the bony structures were assumed to be linearly elastic. The multilayer FEM model containing thighbone, tibia, fibula, kneecap, soft tissue was formed after meshing. Diverse forces were imposed on the FEM model to simulation reposition surgery. The results showed that the multilayer FEM model can represent tissue deformation more accurately.