Abdelaal Osama, Darwish Saied, El-Hofy Hassan, Saito Yoshio
1 Department of Mechanical and Industrial Engineering, College of Engineering, Majmaah University, Majmaah, Saudi Arabia.
2 Department of Mechanical Engineering, Faculty of Engineering, Assiut University, Assiut, Egypt.
Int J Artif Organs. 2019 Jun;42(6):271-290. doi: 10.1177/0391398818815479. Epub 2018 Dec 11.
There are several commercially available hip implant systems. However, for some cases, custom implant designed based on patient-specific anatomy can offer the patient the best available implant solution. Currently, there is a growing trend toward personalization of medical implants involving additive manufacturing into orthopedic medical implants' manufacturing.
This article introduces a systematic design methodology of femoral stem prosthesis based on patient's computer tomography data. Finite element analysis is used to evaluate and compare the micromotion and stress distribution of the customized femoral component and a conventional stem.
The proposed customized femoral stem achieved close geometrical fit and fill between femoral canal and stem surfaces. The customized stem demonstrated lower micromotion (peak: 21 μm) than conventional stem (peak: 34 μm). Stress results indicate up to 89% increase in load transfer by conventional stem than custom stem because the higher stiffness of patient-specific femoral stem proximally increases the custom stem shielding in Gruen's zone 7. Moreover, patient-specific femoral stem transfers the load widely in metaphyseal region.
The customized femoral stem presented satisfactory results related to primary stability, but compromising proximo-medial load transfer due to increased stem cross-sectional area increased stem stiffness.
市面上有多种商用髋关节植入系统。然而，对于某些情况，基于患者特定解剖结构设计的定制植入物可为患者提供最佳的植入解决方案。目前，医疗植入物个性化的趋势日益明显，增材制造已融入骨科医疗植入物的制造过程。
本文介绍了一种基于患者计算机断层扫描数据的股骨柄假体系统设计方法。采用有限元分析来评估和比较定制股骨部件与传统股骨柄的微动及应力分布。
所提出的定制股骨柄在股骨髓腔与柄表面之间实现了紧密的几何贴合与填充。定制柄的微动（峰值：21μm）低于传统柄（峰值：34μm）。应力结果表明，传统柄的载荷传递比定制柄高出89%，这是因为患者特定股骨柄近端较高的刚度增加了Gruen 7区定制柄的应力遮挡。此外，患者特定股骨柄在干骺端区域广泛传递载荷。
定制股骨柄在初始稳定性方面表现出令人满意的结果，但由于柄横截面积增加导致柄刚度增加，近端内侧载荷传递受到影响。
