体液环境下金属—聚乙烯髋关节表面摩擦学性能分析

发布时间：2018-06-08 19:41

本文选题：人工髋关节 + 金属-聚乙烯(MPE)　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：人工全髋关节置换术(THA)是最成熟有效的骨科矫形手术之一,可有效改善关节疼痛,提高患者生活质量。目前,随着患者人群的年轻化趋势,对髋关节的寿命提出了新的挑战。对关节摩擦界面摩擦学性能的研究可以从本质上了解人工关节失效的原因,提出改善措施,从而提高关节使用寿命。本文主要通过原子力显微镜(AFM)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)、傅里叶红外光谱(FTIR)等分析测试手段,对体内翻修取出的三对金属-聚乙烯(MPE)样品进行力学性能和化学成分的测定。之后进行了体外模拟实验想探究附着物形成的过程及表界面因素对其形成过程的影响。实验研究结果表明:(1)通过对体内取回的3对金属-聚乙烯样品进行研究,发现1号样品,金属和聚乙烯对磨的界面上均有吸附物形成;而另外2号和3号样品,均没发现任何吸附现象。为进一步确定吸附物的成分,对吸附物进行了FTIR与XPS测量,发现与传统结论不同,附着物的成分不只是变质蛋白质,而是变质蛋白质与聚乙烯颗粒的混合物。而AFM测得附着物表面黏附力分布在两个不同的区间,则进一步证实了上述结论。(2)通过体外模拟实验,发现在静态吸附实验时,有明显的蛋白质分子的吸附现象;但是在用原子力显微镜进行动态吸附试验时,并未发现很明显的吸附现象。究其原因,可能是因为在进行动态吸附试验时,原子力显微镜的探针针尖比较尖,导致活动过程中有部分蛋白质分子会吸附在探针尖端上,也有可能是蛋白质分子已经吸附在钴铬钼合金表面,在进行形貌测量时,针尖将已经吸附上的蛋白质分子划下来,导致出现蛋白质分子没有发生吸附的假象。但总而言之,体外形成的吸附膜与基底之间的结合力并不如体内形成的牢固。(3)通过纳米压痕仪对三个球头于聚乙烯髋臼杯表面进行硬度与杨氏模量以及成分的测量,发现三个球头的基本属性并无明显区别,而1号髋臼杯特性与其他两个明显不同,因此推测髋臼杯的特性不同可能会导致体内的润滑机制存在差异,进而影响吸附物的形成。通过分析得出,如果髋臼杯硬度较小且表面有一些微织构则有利于使摩擦界面保持在弹流润滑状态;反之,如果髋臼杯硬度较大且表面光滑,则容易使摩擦界面进入边界润滑状态,造成摩擦生物膜的形成。
[Abstract]:Total hip replacement (THA) is one of the most mature and effective orthopedic surgery, which can effectively improve the pain of joint and improve the quality of life of patients. At present, with the younger trend of patients, the life span of hip joint presents a new challenge. The study on the tribological properties of the joint friction interface can essentially understand the causes of the failure of the artificial joint and put forward some measures to improve the service life of the joint. In this paper, the mechanical properties and chemical composition of three pairs of metal-polyethylene MPEG samples were determined by means of atomic force microscope (AFM) X-ray diffractometer (AFM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and so on. Then in vitro simulation experiments were carried out to explore the process of attachment formation and the influence of surface interface factors on the formation process. The experimental results show that through the study of three pairs of metal-polyethylene samples taken from the body, it is found that the adsorbents are formed on the interface between metal and polyethylene on the grinding interface of sample No. 1, and on the other two and three samples. No adsorption was found. In order to further determine the composition of the adsorbents, FTIR and XPS measurements of the adsorbents were carried out. It was found that, unlike the traditional conclusions, the components of the adsorbents were not only the modified proteins, but the mixture of the modified proteins and the polyethylene particles. However, AFM measurements showed that the adhesion force on the surface of the attachment was distributed in two different regions, which further confirmed the above conclusion. (2) through the in vitro simulation experiment, it was found that there was an obvious adsorption phenomenon of protein molecules in the static adsorption experiment. However, no obvious adsorption phenomenon was found in the dynamic adsorption test by atomic force microscope. The reason for this may be that during the dynamic adsorption experiment, the tip of the probe tip of the atomic force microscope is relatively sharp, leading to some protein molecules adsorbing on the tip of the probe during the process of activity. It is also possible that the protein molecules have been adsorbed on the surface of cobalt-chromium-molybdenum alloy. When the surface morphology is measured, the protein molecules that have been adsorbed on the tip of the needle are cut off, resulting in the false appearance that the protein molecules have not been adsorbed. But in a word, the adhesion between the adsorbed membrane and the substrate formed in vitro was not as firm as in vivo.) the hardness and Young's modulus and composition of the three ball heads on the surface of the acetabular cup of polyethylene were measured by nano-indentation instrument. It was found that there was no obvious difference in the basic properties of the three ball heads, but the characteristics of the No. 1 acetabular cup were obviously different from those of the other two. Therefore, it was speculated that the different characteristics of the acetabular cup might lead to the difference of the lubrication mechanism in vivo, and then affect the formation of the adsorbent. The results show that if the acetabular cup has a small hardness and some microtexture on the surface, the friction interface will be kept in an elastohydrodynamic state, whereas if the acetabular cup has a high hardness and a smooth surface, The friction interface is easy to enter the boundary lubrication state, resulting in the formation of friction biofilm.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R687.4;R318.1

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