Tribocorrosion in Modular Hip Joint Junctions-A Parametric Mechanistic Study

描述(由申请人提供)：关节炎影响着5000万美国成年人(其中大部分是65岁)，每年的成本为1280亿美元，仍然是美国最常见的残疾原因。到2030年，估计有6700万成年人(四分之一) 预计会受到关节炎的影响。在严重的情况下，全髋关节置换术(THR)被认为是一种经济有效且临床成功的干预措施。功能良好的THR应该是耐用的(持续患者一生)，并使痛苦的患者能够继续正常生活，对宿主的副作用最小。目前，THR的平均寿命估计为15年，最有可能的是多次翻修手术，特别是在年轻患者的情况下。金属基髋关节假体的主要问题之一是股骨柄在模块连接处的松动和随后的失效。在腐蚀环境中，由于机械微动(微动)和两种金属的接触的耦合作用，模块结一直受到严重关注，主要是由于电偶耦合导致腐蚀动力学的变化。许多回收的金属植入物的表面分析报告已经证明了模块连接处的微动腐蚀的证据。以往关于模块接头微动腐蚀的研究报告了机械辅助腐蚀(MAC)的有害作用，它是与机械磨损相关的腐蚀速度的不可预测的加速。因此，将摩擦学和腐蚀联系起来的摩擦腐蚀协同方法对于确定模块接头的失效路径是必要的。在这项研究中，将对钛和CoCrMo合金在模拟连接环境中影响摩擦腐蚀行为的基本机理进行研究。这项技术将解决机械作用、电化学降解、金属离子和存在于模块结界面上的磨屑之间的相互作用。本应用程序的目标是清楚地定义启用 髋关节假体在模块连接处的早期失效。我们提出了以下具体目标。目的1：确定潜在的微动区域以及pH水平和载荷对腐蚀倾向的影响。目的2：研究金属界面的电化学特性和腐蚀动力学随pH和载荷的变化目标3：建立钛和CoCrMo合金的摩擦腐蚀协同模型，并确定其机理转变为pH和微动制度的函数。预计该项目完成后，将确定与摩擦腐蚀相关的失效机制，并提出设计改进建议，以提供更安全的模块化连接，从而帮助NIAMS为关节炎危急阶段的患者提供长期解决方案。PHS 398/2590(06/09版)页面延续格式页面

DESCRIPTION (provided by applicant): Arthritis affects 50 million U.S. adults (most of whom are aged <65 years) with costs of $128 billion annually, and continues to be the most common cause of disability in the United States. By 2030, an estimated 67 million adults (one in four) are expected to be affected by arthritis. In severe cases, total hip replacements (THR) are accepted as a cost-effective and clinically successful intervention. A well functioning THR should be one that is durable (lasting for the duration of the patient's life) and enables the suffering patient o continue a normal life with minimum side effects on the host body. Currently, the average life span of a THR is estimated at 15 years most likely followed by multiple revision surgeries, particularly in the case of younger patients. One of the major concerns for metal-based hip implants is the loosening and subsequent failure of the femoral stem at the modular junction. The modular junction has been of serious concerns because of the coupled action of mechanical micro-motions (fretting) and the contact of two metals while in a corrosive environment that causes variations in the corrosion kinetics mainly due to galvanic coupling. Numerous surface analysis reports of retrieved metal implants have demonstrated evidence of fretting-corrosion at modular junctions. Previous studies on the fretting-corrosion of modular junctions reported the detrimental role of mechanically assisted corrosion (MAC) which is an unpredictable acceleration in the corrosion rates in association with mechanical wear. Hence, the synergistic approach of tribocorrosion that links tribology and corrosion is necessary to identify the pathways of failure at modular junctions. In this investigation the fundamental mechanisms influencing the tribocorrosion behavior of Ti and CoCrMo alloy in a simulated joint environment will be conducted. This technique will address the interaction between mechanical action, electrochemical degradation, metal ions and wear debris present at the modular junction interface. The objective in this application is to clearly define the potential mechanisms enabling the early failure of hip prostheses at the modular junction. We propose the following specific aims. Aim 1: Identify potential fretting regimes and the influence of pH level and load on the corrosion tendency. Aim 2: Study the electrochemical characteristics of the metal interface and the variability of the corrosion kinetics as a function of pH and load Aim 3: Develop a tribocorrosion synergistic model for Ti and CoCrMo alloys and identify the mechanistic transitions as a function of pH and fretting regime. It is expected that after the completion of ths project the failure mechanisms related to tribocorrosion will be determined and design improvements can be proposed to provide a safer modular junction that will assist the NIAMS mission of long-term solutions for the patients at a critical stage of arthritis. PHS 398/2590 (Rev 06/09) Page Continuation Format Page