股骨假体仿生微结构设计与分析

Design and Analysis of Biomimetic Microstructure of Femoral Prosthesis

目前全髋关节假体性能与真实人体骨骼之间存在巨大差异,容易导致术后假体失稳,仿生微结构可有效解决由于应力遮挡引起的假体失稳问题。基于此,设计了新型仿生微结构股骨假体,以仿生结构(六面体立方、面心立方和体心立方单元结构)构建模型,模型之间保持相近的孔隙率(43%),进行有限元仿真模拟压缩试验,分析仿生微结构的变形、屈服应力、弹性模量等。研究发现,结构的等效弹性模量下降到24.0 GPa左右,与人体皮质骨17.0 GPa相近,其中体心立方结构最小,为22.2 GPa。在3种模型中,六面体立方的稳定性、刚度最强;体心立方的位移最大。研究表明,多孔仿生微结构能够降低弹性模量,改善应力遮挡问题,并对骨骼内生长具有促进作用。

At present, there is a huge difference between the performance of total hip prosthesis and the real human skeleton, which is easy to lead to the instability of the prosthesis after operation. The biomimetic microstructure can effectively solve the problem of prosthesis instability caused by stress shielding. A new type of biomimetic femoral prosthesis was designed, and the biomimetic models were constructed with hexahedral cubic, face-centered cubic and body-centered cubic unit structures. The porosity of the models was kept close(43%), and the compression test was simulated by finite element simulation to analyze the deformation, yield stress and elastic modulus of the biomimetic microstructure. The results showed that the equivalent elastic modulus of the structure decreased to about 24.0 GPa, which was close to 17.0 GPa, the human cortical bone, and the body-centered cubic structure was the least, which was 22.2 GPa. Among the three models, the hexahedral cube has the strongest stability and stiffness. The body-centered cube has the greatest displacement. The results show that the porous bionic microstructures can reduce the elastic modulus, improve the stress shielding problem, and promote the growth of bone.