Compression fracture simulation of osteoporotic trabecular bone in ovariectomized rats / 中国组织工程研究

ABSTRACT

BACKGROUND: At present, related finite element models have been used to simulate the femoral fracture, and the effects of loading rate, loading angle and cancellous bone on the fracture of hip have been discussed. However, the fracture simulation of trabecula is still lack of relevant research. OBJECTIVE: To simulate the biomechanical process of osteoporotic trabecular compression fracture in ovariectomized rats. METHODS: The right femur of ovariectomized rats was scanned at the distal end of femur by Micro-CT. The microstructure parameters and three-dimensional model of the region of interest of the rat femur were obtained. After geometric optimization in Geomagic Studio, they were pretreated in HyperMesh 14.0, including volume mesh division, setting material property parameters, boundary conditions, setting load of 1 200 N, acting time of 2 ms, and they were calculated in LS-DYNA software. RESULTS AND CONCLUSION: (1) The bone trabeculae in the region of interest showed uneven spatial distribution. (2) The bone trabeculae with small volume and small number first presented deformation fracture, and the plate shape and bone trabeculae with large volume finally demonstrated fracture collapse. (3) The change trend of von Mises stress was roughly the same as that of bone trabeculae fracture collapse. The fracture collapse process of bone trabeculae in the region of interest included vertical collapse and horizontal torsion, in which the degree and rate of horizontal torsion were lower than that of vertical collapse, making the size and rate of cross-section torsion angle less than that of coronal plane angle. (5) The increase and peak value of shear stress of failure unit were smaller than Von-mises stress. (6) These results indicate that fracture collapse of bone trabecula is a complex process, including deformation and angle of different planes.