Trabecular deformations during screw pull-out: a micro-CT study of lapine bone
Trabecular deformations during screw pull-out: a micro-CT study of lapine bone
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DOI：
10.1007/s10237-017-0891-9
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发表时间：
2017-08-01
影响因子：
3.5
通讯作者：
Persson, Cecilia
中科院分区：
文献类型：
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作者：
Joffre, Thomas;Isaksson, Per;Persson, Cecilia
由于松质骨微孔结构复杂，骨内植入物，如螺丝，在松质骨中的机械固定是具有挑战性的。开发新的螺钉设计以改善骨折固定，特别是在高孔隙率的骨质疏松骨中，需要深刻理解结构系统植入物/骨小梁在机械载荷下如何相互作用。在这项研究中，进行了螺纹式种植体的拔出试验。首先将螺丝钉插入兔股骨的松质骨中，然后在计算机断层扫描仪中从骨中拔出。测试在某些加载步骤被中断，以获取3D图像。然后用数字体积相关技术对图像进行分析，以估计测试过程中骨骼内部的变形和应变场。结果表明，最大剪切应变集中在螺杆内外径之间，而压应变在距螺杆较远的位置处出现。拉伸应变略小一些。应变集中和骨小梁破坏的位置提供了实验信息，可用于开发新的螺钉设计和/或验证数值模拟。
The mechanical fixation of endosseous implants, such as screws, in trabecular bone is challenging because of the complex porous microstructure. Development of new screw designs to improve fracture fixation, especially in high-porosity osteoporotic bone, requires a profound understanding of how the structural system implant/trabeculae interacts when it is subjected to mechanical load. In this study, pull-out tests of screw implants were performed. Screws were first inserted into the trabecular bone of rabbit femurs and then pulled out from the bone inside a computational tomography scanner. The tests were interrupted at certain load steps to acquire 3D images. The images were then analysed with a digital volume correlation technique to estimate deformation and strain fields inside the bone during the tests. The results indicate that the highest shear strains are concentrated between the inner and outer thread diameter, whereas compressive strains are found at larger distances from the screw. Tensile strains were somewhat smaller. Strain concentrations and the location of trabecular failures provide experimental information that could be used in the development of new screw designs and/or to validate numerical simulations.