FEASIBILITY STUDY--BONE DYNAMIC STRENGTH WITH IMPROVED CEMEMT

在美国，每年进行超过20万例关节置换手术。 美国的 虽然基本上是成功的，但据报道， 大量的长期故障，其中许多涉及 丙烯酸骨水泥和/或界面的破坏 在骨头和骨水泥之间 已经尝试 通过去除部分内部孔隙来改善水泥， 在混合过程中离心的方法。 在我们的实验室里， 最近开发了一种真空混合碗， 甚至更多的孔隙度，并产生一种上级的水泥 在机械单轴拉伸和压缩强度以及 具有大得多的拉伸疲劳寿命。 的一个大问题 如果真空混合水泥的上级性能 其本身将转移到骨水泥/骨界面， 增强的机械结合。 使用长期低负荷循环 通过裂纹扩展产生水泥断裂的测试模式， 建议研究增强水泥的可行性， 形成更好的骨水泥/骨结合。 虽然精通高负荷的测定，塑性 合成牙科材料的变形单轴力学性能， 医学材料，主要研究者必须 为了学会学习， 低周反复、复杂弹性加载的断裂力学， 多部件接口 研究计划是创建骨水泥/骨界面样本， 特别注意混合技术等变量， 就业率和压力，加上性质和准备的 尸体松质骨床。 然后，将这些标本 搭接剪切、环剪、弯曲和裂纹等界面试验 传播 这些将在37 ℃生理模拟下进行 液体在准静态和更临床相关的长期 长期，低幅度循环动态载荷，以评估 确定断裂机制的可行性， 增强骨水泥/骨界面的强度。

Over 200,000 total joint replacements are performed yearly in the United States. Although basically succesful, there are reported a significant number of long term failures, many of which involve breakdown of the acrylic bone cement and/or the interface between the bone and the cement. Attempts have been made to improve the cement by removing some of its internal porosity by means of centrifugation during mixing. In our laboratory a partial vacuum mixing bowl has been recently developed which removes even more of the porosity and creates a cement which is superior in mechanical uniaxial tensile and compression strength as well as having much greater tensile fatigue life. A major question remains if the superior properties of the vacuum mixed cement itself will transfer to the cement/bone interface to produce an enhanced mechanical bond. Using long term, low loading cyclic testing modes to produce cement fracture by crack propagation, it is proposed to investigate the feasibility of stronger cements creating better cement/bone bonding. Although well versed in the determination of high load, plastically deforming uniaxial mechanical properties of synthetic dental and medical materials, the principal investigator would have to significantly shift his area of research in order to learn to study the fracture mechanics of low cyclic, elastic loading of complex, multicomponent interfaces. The research plan is to create cement/bone interface specimens, paying great attention to such variables as mixing technique, placement rates and pressures, plus nature and preparation of the cadaveric cancellous bony bed. Then, subject these specimens to interface tests such as lap shear, ring shear, bending and crack propagation. These will be done in 37 C physiologically simulating fluids in both quasi-static and the more clinically relevant long term, low magnitude cyclic dynamic loading in order to evaluate the feasibility of determining the fracture mechanisms and enhancement of the strength of the cement/bone interface.