Rubshtein A P, Makarova E B, Rinkevich A B, Medvedeva D S, Yakovenkova L I, Vladimirov A B
M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 18S. Kovalevskaya St., Ekaterinburg 620990, Russia.
V.D. Chaklin Ural Scientific & Research Institute of Traumatology and Orthopaedics, 7 Bankovskiy per., Ekaterinburg 620014, Russia.
Mater Sci Eng C Mater Biol Appl. 2015;52:54-60. doi: 10.1016/j.msec.2015.03.015. Epub 2015 Mar 13.
The porous titanium implants were introduced into the condyles of tibias and femurs of sheep. New bone tissue fills the pore, and the porous titanium-new bone tissue composite is formed. The duration of composite formation was 4, 8, 24 and 52 weeks. The formed composites were extracted from the bone and subjected to a compression test. The Young's modulus was calculated using the measured stress-strain curve. The time dependence of the Young's modulus of the composite was obtained. After 4 weeks the new bone tissue that filled the pores does not affect the elastic properties of implants. After 24 and 52 weeks the Young's modulus increases by 21-34% and 62-136%, respectively. The numerical calculations of the elasticity of porous titanium-new bone tissue composite were conducted using a simple polydisperse model that is based on the consideration of heterogeneous structure as a continuous medium with spherical inclusions of different sizes. The kinetics of the change in the elasticity of the new bone tissue is presented via the intermediate characteristics, namely the relative ultimate tensile strength or proportion of mature bone tissue in the bone tissue. The calculated and experimentally measured values of the Young's modulus of the composite are in good agreement after 8 weeks of composite formation. The properties of the porous titanium-new bone tissue composites can only be predicted when data on the properties of new bone tissue are available after 8 weeks of contact between the implant and the native bone.
将多孔钛植入物植入绵羊的胫骨和股骨髁。新骨组织填充孔隙，形成多孔钛-新骨组织复合材料。复合材料形成的持续时间为4周、8周、24周和52周。从骨中取出形成的复合材料并进行压缩试验。使用测得的应力-应变曲线计算杨氏模量。得到了复合材料杨氏模量的时间依赖性。4周后，填充孔隙的新骨组织不影响植入物的弹性性能。24周和52周后，杨氏模量分别增加21%-34%和62%-136%。使用简单的多分散模型对多孔钛-新骨组织复合材料的弹性进行了数值计算，该模型基于将非均质结构视为具有不同尺寸球形夹杂物的连续介质的考虑。通过中间特征，即相对极限抗拉强度或骨组织中成熟骨组织的比例，呈现新骨组织弹性变化的动力学。复合材料形成8周后，计算得到的复合材料杨氏模量与实验测量值吻合良好。只有当植入物与天然骨接触8周后获得新骨组织的性能数据时，才能预测多孔钛-新骨组织复合材料的性能。
