RESUMEN
BACKGROUND:The biomechanical properties of the hip bone are complex in vivo that requires a more efficient and accurate method for the finite element analysis. OBJECTIVE: To develop a musculoskeletal multi-body dynamic model of the patient-specific hip joint after surgery and simulate gait, and to explore the biomechanics of the hip joint. METHODS: CT data of the patient's hip joint postoperatively were collected, three-dimension reconstruction underwent in MIMICS, and materialization and position matched on Geomagic Studio and meshed on Hypermesh. A musculoskeletal multi-body dynamic model of the patient-specific hip joint was established using AnyBody software and simulated the normal movements during walking, then export the muscle force, oint forces, joint moment as the Boundary conditions in finite element analysis. Then, the muscle forces, joint forces and torque were obtained and imported to be the boundary conditions for finite element analysis. The stress and strain values and concentration parts were measured on Abauqus during walking. RESULTS AND CONCLUSION: (1) The maximum value of the joint force in the three directions of the hip joint was 600, 2 000, 100 N at 2.1 seconds. (2) The ilium force was almost only in the Y direction, and the maximum value was 1 000 N. (3) The maximum stress on the hip joint was about 12 MPa at 30% of the gait cycle and the maximum relative displacement was 0.5 mm. (4) To conclude, the stress of the hip after surgery is mainly concentrated on the vicinity of the sacroiliac joint, postersuperior of the acetabulum, middle region of iliac bone, and upper zone of pubic bone; the stress of the hip is higher than that of the normal hip, and the activity intensity should be paid attention during rehabilitation.