Based On Finite Element Contact Analysis Of The Hip Acetabulum Mobile Surgery Biomechanical Simulation Study

The hip joint plays an important role in the musculoskeletal system. However, many hip joint are suffering from coxarthrosis. The contact area of these patients with acetabular dysplasia is normally decreased, and the joint contact is abnormal. An effective operation which called transpositional osteotomy of the acetabulum is widely used in medical field for this kind of disease. It is necessary to research stress distribution in normal walking of daily activities, not only for understanding the pathogenesis of Osteoarthritis, but also for supplying theory basis for transpositional osteotomy. In order to analysis the biomechanical behavior of the diseased hip joint, a three-dimensional model was developed using computer graphical technology. In this model, the geometry of hip joint is based on the data of CT (Computed Tomography) image captured, and sphere is used to represent the shape of cartilage surface. Then the model was meshed by tetrahedral elements for analysis. Concerning the physiological state of cartilage and the forced state of femoral head, we defined the boundary conditions of model and use the software Msc.Marc to compute. During the computation, we adjusted the controllable parameters of the finite element analysis for better convergence. Subsequently, we obtained the stress distribution of the hip joint during a normal walking activity and analyzed the stress concentrating area of the cartilage. By comparing the preoperative biomechanical behavior analysis with the postoperative one we evaluated the clinical effect of transpositional osteotomy. Therefore, based on the physiological properties of hip joint, we obtained the causation of cavitational osteopathosis and the conclusion that the stress concentrated in the anterior and lateral edge of the acetabulum, thereby the pathogenesis of coxarthrosis has been understood.