Although the role of fatigue failure in aseptic loosening of cemented total hip replacements has been extensively studied in femoral components, studies of fatigue failure in cement mantle of acetabular replacements have yet to be reported, despite that the long-term failure rate in the latter is about three times that of femoral components. Part of the reason may be that a complex pelvic bone structure does not land itself readily for a 2D representation as that of a femur. In this work, a simple multilayer model has been developed to reproduce the stress distributions in the cement mantle of an acetabular replacement from a plane strain finite element pelvic bone model. The experimental multilayer model was subjected to cyclic loading up to peak hip contact force during normal walking. Radial fatigue cracks were observed in the vicinity of the maximum tangential and compressive stresses, as predicted by the FE models. Typical fatigue striations were also observed on the fracture surfaces post cyclic testing. The results were examined in the context of retrieval studies, 3D FE analysis and in vitro experimental results using full-sized hemi-pelvic bone models.

中文翻译：

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简化髋臼置换模型的水泥罩疲劳破坏


尽管股骨假体中疲劳失效在骨水泥型全髋关节置换术无菌性松动中的作用已得到广泛研究，但关于髋臼骨水泥套的疲劳失效研究尚未见报道，尽管后者的长期失败率较低。大约是股骨组件的三倍。部分原因可能是复杂的骨盆骨结构不容易像股骨那样进行二维表示。在这项工作中，开发了一个简单的多层模型，用于根据平面应变有限元骨盆骨模型再现髋臼置换物的水泥罩中的应力分布。实验多层模型在正常行走期间承受循环负载直至达到峰值髋部接触力。正如有限元模型预测的那样，在最大切向应力和压应力附近观察到径向疲劳裂纹。循环测试后，在断裂表面也观察到典型的疲劳条纹。结果在检索研究、3D FE 分析和使用全尺寸半骨盆骨模型的体外实验结果的背景下进行了检查。