BACKGROUND The surgical success of cementless implants is determined by the evolution of the biomechanical properties of the bone-implant interface (BII). One difficulty to model the biomechanical behavior of the BII comes from the implant surface roughness and from the partial contact between bone tissue and the implant. The determination of the constitutive law of the BII would be of interest in the context of implant finite element (FE) modeling to take into account the imperfect characteristics of the BII. The aim of the present study is to determine an effective contact stiffness [Formula: see text] of an osseointegrated BII accounting for its micromechanical features such as surface roughness, bone-implant contact ratio (BIC) and periprosthetic bone properties. To do so, a 2D FE model of the BII under normal contact conditions was developed and was used to determine the behavior of [Formula: see text]. RESULTS The model is validated by comparison with three analytical schemes based on micromechanical homogenization including two Lekesiz's models (considering interacting and non-interacting micro-cracks) and a Kachanov's model. [Formula: see text] is found to be comprised between 1013 and 1015 N/m3 according to the properties of the BII. [Formula: see text] is shown to increase nonlinearly as a function of the BIC and to decrease as a function of the roughness amplitude for high BIC values (above around 20%). Moreover, [Formula: see text] decreases as a function of the roughness wavelength and increases linearly as a function of the Young's modulus of periprosthetic bone tissue. CONCLUSIONS These results open new paths in implant biomechanical modeling since this model may be used in future macroscopic finite element models modeling the bone-implant system to replace perfectly rigid BII conditions.

中文翻译：

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骨整合的骨-植入物界面的接触刚度的微机械建模。

背景技术非骨水泥植入物的手术成功取决于骨-植入物界面（BII）的生物力学性能的演变。对BII的生物力学行为进行建模的一个困难来自植入物的表面粗糙度以及骨组织与植入物之间的部分接触。考虑到BII的不完美特性，在植入物有限元（FE）建模的背景下确定BII的本构定律将是有意义的。本研究的目的是确定骨集成的BII的有效接触刚度[公式：参见文本]，考虑其微机械特征，例如表面粗糙度，骨-植入物接触比（BIC）和假体周围的骨特性。为此，建立了在正常接触条件下BII的二维有限元模型，并用于确定[公式：参见文本]的行为。结果通过与基于微机械均质化的三种分析方案进行比较，验证了该模型，其中包括两个Lekesiz模型（考虑相互作用和非相互作用微裂纹）和Kachanov模型。根据BII的性质，发现[式：见正文]在1013和1015N / m3之间。对于高BIC值（约20％以上），[公式：参见文字]显示为BIC的非线性增加，而粗糙度粗糙度的函数则降低。此外，[公式：见正文]随粗糙度波长的变化而减小，并随假体周围骨组织的杨氏模量的变化而线性增加。