Hip Implant Design With Three-Dimensional Porous Architecture of Optimized Graded Density
Hip Implant Design With Three-Dimensional Porous Architecture of Optimized Graded Density
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DOI：
10.1115/1.4041208
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发表时间：
2018-11-01
影响因子：
3.3
通讯作者：
Pasini, Damiano
中科院分区：
文献类型：
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作者：
Wang, Yingjun;Arabnejad, Sajad;Pasini, Damiano
即使在功能良好的全髋关节置换术中，应力遮挡也可能继发于显著的种植体周围骨吸收。应力遮挡是由较硬的植入物和相邻骨组织之间的弹性模量的不期望的失配引起的。为了解决这个问题，我们在这里提出了一个微架构的髋关节植入物，由三维（3D）梯度晶格材料与股骨的机械生物相容性的属性。渐近均匀化（AK）用于数值确定植入物的机械和疲劳性能，拓扑优化的无梯度方案用于在植入物微动、孔径、孔隙率和细胞元件的最小可制造厚度决定的多个约束条件下找到多孔植入物的优化相对密度分布。从38岁患者股骨获得，通过术后条件下植入骨和完整骨之间的应变能差异评估骨吸收。数值结果表明，优化的多孔种植体的骨丢失仅为完全实心种植体的42%，这里作为基准，为具有均匀密度的多孔种植体的79%。本研究中提出的结构化髋关节植入物显示出减少骨丢失的临床前景，同时防止植入物微动，从而有助于降低假体周围骨折的风险和翻修手术的可能性。
Even in a well-functioning total hip replacement, significant peri-implant bone resorption can occur secondary to stress shielding. Stress shielding is caused by an undesired mismatch of elastic modulus between the stiffer implant and the adjacent bone tissue. To address this problem, we present here a microarchitected hip implant that consists of a three-dimensional (3D) graded lattice material with properties that are mechanically biocompatible with those of the femoral bone. Asymptotic homogenization (AK) is used to numerically determine the mechanical and fatigue properties of the implant, and a gradient-free scheme of topology optimization is used to find the optimized relative density distribution of the porous implant under multiple constraints dictated by implant micromotion, pore size, porosity, and minimum manufacturable thickness of the cell elements. Obtained for a 38-year-old patient femur, bone resorption is assessed by the difference in strain energy between the implanted bone and the intact bone in the postoperative conditions. The numerical results suggest that bone loss for the optimized porous implant is only 42% of that of a fully solid implant, here taken as benchmark, and 79% of that of a porous implant with uniform density. The architected hip implant presented in this work shows clinical promise in reducing bone loss while preventing implant micromotion, thereby contributing to reduce the risk of periprosthetic fracture and the probability of revision surgery.