Biomechanical Study on Different fixation Methods of Cannulated Screws for Posterior Malleolus Fracture / 医用生物力学

Objective To study biomechanical effects of cannulated screws at different fixation angles on posterior malleolus fracture based on finite element method, so as to determine the best fixation method of cannulatedscrew. Methods The finite element model of ankle joint, including tibia, fibula, astragalus, corresponding cartilage and ligaments was reconstructed using CT images, and 1 / 2 posterior malleolus fracture model was established on the basis of verifying its validity. The biomechanical effects of cannulated screw fixation on posterior malleolus fracture fixation model were analyzed. Results Compared with 0°,5°,10°,20° fixation model, the 15° fixation model had the smallest displacement. The screw stress of 15° fixation model was lower than that of 5°, 10°, 20° fixation model, and higher than that of 0° fixation model. But when the screw fixation angle was 0°, the peak contact pressure of ankle joint was much larger than that of normal ankle joint, which was easy to cause traumatic osteoarthritis. Conclusions Cannulated screw is safe and effective for treating posterior malleolus fracture which is less than 1 / 2 fragment size. The displacement and stress of the model are different at different fixation angles of screws. When the fixation angle of screw is 15°, the biomechanical stability is the best, which can be used to guide clinical operation.

Research Progress in Seeding Cells of Peripheral Nerve / 生物医学工程学杂志

Seeding cells play an important role in the peripheral nerve damage repair. Seeding cells studied conse- quently in peripheral nerve are Schwann cells, bone marrow mesenchymal stem cells and neural stem cells. Schwann cells, the first seeding cells, are various unique glial cells in the peripheral nervous system, which can form the myelin sheath for insulation and package of the neuron projecting axons in the peripheral nervous system so that the conduction velocity of the nerve signal was accelerated. It can be proved that Schwann cells played an important role in the maintenance of peripheral nerve function and in the regeneration process after peripheral nerve injury. The second, bone marrow mesenchymal stem cells are the various mesenchymal stem cells mainly exist in the systemic connective tissues and organs. These functional stem cells are often studied at present, and it has been found that they have exuberant proliferation and differentiation potentials. Neural stem cells, mentioned the third in sequence, are the kind of pluripotent cells with multi-directional differentiation, which could conduct the self-renewal function, and generate and differentiate neurons, astrocytes and oligodendrocytes through asymmetric cell division. These three types of seed cells are discussed in this paper.

Finite Element Analysis of Intravascular Stent Based on ANSYS Software / 生物医学工程学杂志

This paper adopted UG8.0 to bulid the stent and blood vessel models. The models were then imported into the finite element analysis software ANSYS. The simulation results of ANSYS software showed that after endothelial stent implantation, the velocity of the blood was slow and the fluctuation of velocity was small, which meant the flow was relatively stable. When blood flowed through the endothelial stent, the pressure gradually became smaller, and the range of the pressure was not wide. The endothelial shear stress basically unchanged. In general, it can be concluded that the endothelial stents have little impact on the flow of blood and can fully realize its function.

Stress analysis of artificial bionic knee joint based on UG6.0 NX NASTRAN / 生物医学工程学杂志

This article introduces the basic principles of finite element analysis in biomechanics, focusing on the basic principles of a variety of finite element analysis software, and their respective characteristics. In addition, it also de scribes the basic stress analysis of UGNX6.0 NASTRAN analysis for artificial knee process, i. e. the choice of the type, material definition, the set of constants, finite element mesh division and the finite element results of the analysis. Finite element analysis and evaluation of the design of personalized artificial knee were carried out, so that the rationality of the geometric design of the structure of the experimental design of artificial knee has been verified.