DOI: 10.3724/SP.J.1249.2021.02201
应力遮挡效应是影响假体修复手术效果的主要因素,由于目前3D打印钛合金植入假体与人体骨骼之间本构关系的差异会导致骨缺损修复手术产生应力遮挡现象.针对这个问题,分析单元组织结构与模型弹性模量之间的映射关系,建立了符合人体骨骼本构模型的多孔结构植入假体结构模型,并利用优化的打印参数打印钛合金假体进行验证实验.研究发现,当线能量密度为269.1 J/mm3时,3D打印钛合金假体的弹性模量可降低至31.51 GPa; 采用diamond结构且孔隙率在70%～80%的多孔结构可与人体皮质骨的模量一致,并建立二者之间对应关系.通过建立单元组织结构与人体皮质骨模量的映射关系规律,准确反映了假体值入的模量随3D打印多孔结构单元尺寸增大而增大、随孔隙率增大而减小的规律,为消除应力遮挡现象的研究提供理论支撑.
Stress shielding effect is the main factor which affects the reconstructive surgery effect of prosthesis. At present, the difference of constitutive relationship between 3D printed titanium alloy prosthesis implant and human bone leads to the stress shielding phenomenon in bone defect repairing surgery. To solve this problem, this paper establishes a porous structure model of prosthesis implantation conforming to the constitutive model of human bone through analysis on the mapping relationship between unit tissue structure and elastic modulus of model. And titanium alloy is printed with optimized print parameters for 3D printer to testify the experiment. The study finds that the elastic modulus of 3D printed titanium alloy could be reduced to 31.51 GPa when the linear energy density is 269.1 J/mm3; the porous structure with diamond structure and porosity of 70%-80% could be consistent with the modulus of human cortical bone and the corresponding relationship between them could be established. This paper builds the law of mapping relationship between unit tissue structure and modulus of human cortical bone, which accurately reflects the rule that the modulus of prosthesis implant increases with the increase of the size of 3D printing porous structure unit and decreases with the increase of porosity. It provides theoretical support for research of eliminating stress shielding phenomenon.
