【作者】 华子恺；

【导师】 张建华；

【作者基本信息】 上海大学 ， 机械工程， 2011， 博士

【摘要】 人工关节置换术,已成为治疗关节疾病的一种重要手段,其借助于人工材料所制成的植入性假体,即人工关节,用以替代病变或损伤的关节。在人工关节的研究和临床随访中发现,其长期可靠性以及功能性方面的问题与其生物摩擦学表现存在密切联系。因此,如何从生物摩擦学角度对人工关节进行有效润滑,以及开发科学的测试技术,对于提高关节置换者的生命质量、提升人工关节性能而言,具有重要的意义。本文主要从两个方面开展对人工关节生物摩擦学的研究。其一,从人工关节润滑技术角度出发,开发了仿生关节滑液(复合滑液),对其生物相容性、润滑性能、电化学性能进行了试验研究;此外,将表面织构技术引入人工关节的润滑中,考察了其对硬相人工关节材料的摩擦学与声学作用。其二,在人工关节生物摩擦学测试方面,分别针对人工关节成品与人工关节材料的摩擦学测试,开发了多功能髋关节模拟试验装置与复合运动销盘试验装置,并进行了相应测试方法研究;此外,研制了人工关节材料摩擦声学测试系统,用以研究硬相人工关节的摩擦异响问题。主要研究内容包括以下几个方面:针对仿生关节滑液(复合滑液),进行生物相容性的测试,证明了其具有良好的生物相容性;通过对UHMWPE与CoCrMo人工关节的磨损试验,发现复合滑液对该类摩擦副的润滑性能优于对比组中的滑液,并能在UHMWPE表面形成蛋白质薄膜润滑;作为治疗性成分的阿伦磷酸钠对UHMWPE磨粒大小有一定积极影响。此外,针对金属人工关节的润滑,试验研究了仿生关节滑液的电化学性能,并考察其对CoCrMo与CoCrMo摩擦副的润滑性,发现CoCrMo材料的摩擦磨损性能主要取决于复合滑液的机械及电化学性能。滑液中透明质酸钠通过其分子结构等因素决定了复合滑液的粘度,对CoCrMo摩擦副界面间的摩擦系数产生了较大的影响;白蛋白能够在CoCrMo摩擦副表面形成蛋白质沉积薄膜,起到减摩保护作用,但是由于电化学反应,会加重CoCrMo材料的腐蚀;阿伦磷酸钠对金属关节具有抗磨、抗腐蚀的积极作用。针对硬相人工关节摩擦异响问题,提出将表面织构应用于人工关节之上,改善其润滑情况。首先,针对表面织构的参数设计建立了弹性流体动力润滑模型,分析比较了织构的径深比、密度以及摩擦副材料、运动参数对润滑状态的影响。之后,在此基础上对硬相人工关节材料表面进行激光织构加工工艺的探索,采用激光填充一次成型加工方式,控制织构间距,改善了热效应区域等加工问题;最后,基于所开发的摩擦声学测试系统,开展了表面织构处理后陶瓷材料的摩擦声学测试,试验证实织构在陶瓷人工关节材料表面能够起到一定的减摩降噪的效果,且摩擦学结果与声学测量结果相吻合,初步证明了表面织构有利于降低了异响的发生率,在人工关节方面具有潜在的应用前景。针对人工关节成品、人工关节材料的摩擦学测试,以及人工关节摩擦声学问题的三方面内容,分别研制了多功能髋关节模拟试验装置、复合运动销盘试验装置、人工关节材料摩擦声学测试系统,并进行了测试方法探索。结果表明:(a)多功能髋关节模拟试验装置的运动形态、模拟步态、受力曲线均符合对人体髋关节的运动重现的要求,所产生的人工关节试验磨损率接近于近期临床结果,满足人工髋关节的成品摩擦学测试的要求,此外,通过部件的转换,能够支持普通的销盘摩擦学试验;(b)所开发的复合运动销盘试验装置为人工关节材料摩擦学测试提供了台架,基于该装置的人工关节材料测试结果比普通销盘试验与临床结果更为接近,该种测试方法满足人工关节材料的前道摩擦学测试要求;(c)人工关节材料摩擦声学测试系统,为人工关节摩擦学与声学研究的交叉研究提供了平台,基于该系统进行了试验初试及方法探索,试验结果证明了该系统及测试方法的可行性。更多还原

【Abstract】 Joint replacement, is one of the most effective treatments to joint diseases, in which an arthritic or damaged joint is replaced by an artificial joint. Long term clinical results show that wear of artificial joints determines the lifetime of such implants. The biotribological performance of prostheses has significant impact on its reliability and functionality. Therefore, researches on artificial joint lubrication and tribological testing are required, in order to qualify the tribological property of the artificial joints and prolong the product duration.In this thesis, researches cover two main aspects, including lubrication technology investigation and development of tribological test apparatus in related to artificial joints. In artificial joint lubrication, biomimetic synovial fluids were developed; biocompatibility, rheology, electrochemical and tribological property were experimental studied. Moreover, surface texturing was applied in hard-on-hard artificial joint materials, tribo-acoustic performance were carried out for fundamental validation. In the second aspect, tribological test apparatus, such as multi-functional hip joint simulator, multi-directional pin on disk tribometer, were built up for wear tests of artificial products and materials. Furthermore, a tribo-acoustic test system was also established for the initial study on friction induced squeaking phenomenon in hard-on-hard artificial joints. Main research points and conclusions can be reached as below,In the study of biomimetic synovial fluids, by biocompatibility test, the results validated safety and non-toxicity of such fluids towards human body. Wear test were carried out on UHMWPE/CoCrMo artificial joints, results showed that biomimetic synovial fluids had the best lubrication performance among all the fluids in this study. And protein membrane could be observed on the surface of UHMWPE in biomimetic synovial fluids, which provided thin film lubrication towards the wear couples. As a therapeutic composition, alendronic acid sodium had positive impact on the UHMWPE wear debris. For metal-on-metal artificial joint lubrication, the electrochemical property of biomimetic synovial fluids has been investigated. In tribological test of CoCrMo on CoCrMo materials, friction and wear were mainly dominated by the mechanical and electrochemical performance of the biomimetic synovial fluids. By orthogonal analysis, results showed that hyaluronic acid dominated the viscosity of the fluids, thus directly affected the friction between CoCrMo balls. High albumin concentration would reduce friction, while increasing wear rate due to the electrochemical effect. Alendronic acid sodium was found to reduce the biocorrosion of CoCrMo as well as improving lubrication.Surface texturing technology has been introduced and applied on hard-on-hard artificial joints in regard to the friction induced squeaking and wear problems. An elastohydrodynamic (EHL) model was set up for surface texture designing reference. Then, laser surface texturing processes on hard artificial joint materials was studied and optimized. Finally, via a tribo-acoustic system, laser surface textured ceramic materials were tested. Results showed that surface texture helped to reduce the squeaking sound emission as well as the friction, consequently, verified the potential application of this technology in artificial joints.Concerned artificial joint product level, material level tribological tests and tribo-acoustic test, three test equipments, as one multi-functional hip joint simulator, one multi-directional pin on disk tribometer and a tribo-acoustic test system, were designed, built and validated. Moreover, test methods were also proposed and testified. Preliminary test results summarized, (a) the multi-functional hip joint simulator, generated by a hip joint simulator and a general pin on disk module, could support both artificial hip joint wear tests and common material tribological experiments. Motion configurations and wear factors observed in this simulator agreed well with those in clinics, and it offered a reliable test bench for artificial hip joint products. (b) The multi-directional pin on disk test methods provided a better solution for artificial joint material level wear tests. Compared with common pin on disk tests, experimental results in such test apparatus was more accurate referring to clinical issues. (c) Via the tribo-acoustic test system, both tribological and acoustic signal could be measured simultaneously, thus, providing a test platform and a feasible methodology for the fundamental understanding of friction induced squeaking phenomenon in hard-on-hard artificial joints and investigation of other potential solutions toward this problems.更多还原