Custom reverse shoulder implants represent a valuable solution for patients with large bone defects. Since each implant has unique patient-specific features, finite element (FE) analysis has the potential to guide the design process by virtually comparing the stability of multiple configurations without the need of a mechanical test. The aim of this study was to develop an automated virtual bench test to evaluate the initial stability of custom shoulder implants during the design phase, by simulating a fixation experiment as defined by ASTM F2028-14. Three-dimensional (3D) FE models were generated to simulate the stability test and the predictions were compared to experimental measurements. Good agreement was found between the baseplate displacement measured experimentally and determined from the FE analysis (Spearman’s rank test, p < 0.05, correlation coefficient ρs = 0.81). Interface micromotion analysis predicted good initial fixation (micromotion <150 µm, commonly used as bone ingrowth threshold). In conclusion, the finite element model presented in this study was able to replicate the mechanical condition of a standard test for a custom shoulder implants.

中文翻译：

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定制肩部植入物的有限元分析提供了初始稳定性的准确预测

定制的反向肩植入物为患有大骨缺损的患者提供了一种有价值的解决方案。由于每种植入物都具有独特的患者特定功能，因此有限元（FE）分析具有通过虚拟比较多种配置的稳定性而无需进行机械测试的潜力，从而可以指导设计过程。这项研究的目的是通过模拟ASTM F2028-14定义的固定实验，开发一种自动化的虚拟台架试验，以评估定制肩部植入物在设计阶段的初始稳定性。生成了三维（3D）有限元模型来模拟稳定性测试，并将预测结果与实验测量值进行比较。实验测量的底板位移与有限元分析（斯皮尔曼等级测试，p <0.05，相关系数ρs= 0.81）。界面微动分析可预测良好的初始固定（微动<150 µm，通常用作骨骼向内生长阈值）。总之，本研究中提出的有限元模型能够复制定制肩部植入物的标准测试的机械条件。