Wear Testing for Enhanced Prediction of TKR Clinical Performance

描述（由申请人提供）：仅在美国，每年就有超过450，000例手术，全膝关节置换术（TKR）已成为一种常见的外科手术，用于缓解疼痛并增加患病或创伤膝关节的功能活动度。TKR使用寿命的主要限制因素仍然是聚乙烯胫骨衬垫的磨损。预期寿命和体重的增加，以及年轻患者的TKR手术趋势将对未来的器械提出更高的要求。临床前耐久性试验已成为植入物开发期间预测新器械机械性能的标准程序。这些测试程序遵循测试成功策略，需要从日常使用的载荷和运动谱中获得输入数据。然而，最近的研究表明，目前的国际测试标准不能模拟植入交叉韧带保留型膝关节假体的患者步态期间的运动学和动力学条件。此外，目前的协议只关注步行，完全忽略了其他日常生活活动。虽然步行是一天中最频繁的活动，但其他日常体力活动通常会产生更高的胫骨载荷、更大的假体运动和比步行更有害的交叉剪切。实际上，受试部件的磨损特征与体内磨损特征不匹配，无论是磨痕尺寸和形状还是磨损形态。TKR的前侧内侧和外侧关节面不是导致磨损和骨质溶解的唯一表面。聚乙烯内衬背面与金属基板/胫骨托之间的微动导致“背面磨损”。由于背面接触面积较大且可能产生的颗粒较小，因此背面磨损的溶骨性显著性高于正面关节面磨损，尽管背面磨损的准确量化已被证明是困难的。日常体力活动与特定位置TKR佩戴之间的关系也未知。我们假设输入磨损模拟器的运动和力曲线必须来自TKR患者的多次日常活动测量，以便准确再现临床观察到的TKR正面和背面的磨损率和模式。我们提出了三个目标来研究我们的整体假设。在前两个目标中，我们将证明使用TKR患者和多种日常活动的输入配置文件生成更真实的磨损。在第三个目标中，我们将设计和验证一种新的多活性磨损协议，反映真实的体内使用。我们将使用镧系硬脂酸盐的新技术，通过质谱法跟踪血清中的聚乙烯磨损。不同的元件用于不同的TKR界面，以允许原位跟踪正面与背面磨损。将使用具有独特步态和活动信息的检索来验证结果。这些研究有目的地限于市场份额较高的交叉韧带保留型TKR设计。

DESCRIPTION (provided by applicant): With over 450,000 surgeries performed annually in the US alone, total knee replacement (TKR) has become a common surgical procedure to alleviate pain and increase functional mobility in diseased or traumatized knee joints. A major limiting factor to the service life of TKRs remains the wear of the polyethylene tibial liner. Increases in life expectancy and body weight, as well as the trend for TKR surgery in younger patients will put even higher demands on future devices. Preclinical endurance testing has become a standard procedure to predict the mechanical performance of new devices during implant development. These testing procedures follow a test-to-success strategy, which require input data derived from the load and motion spectrum of daily use. However, recent studies show that current international testing standards do not mimic the kinematic and kinetic conditions during gait for patients implanted with a cruciate retaining knee prosthesis. In addition, current protocols focus only on walking, completely omitting other activities of daily living. Although walking is the most frequent activity throughout the day, other daily physicals activities often generate higher tibial loads, larger prosthetic movements, and more detrimental cross-shear than walking. Indeed, wear features of tested components do not match those worn in vivo, neither regarding wear scar size and shape, nor wear morphology. The frontside medial and lateral bearing surfaces of TKRs are not the only surfaces which contribute to wear and osteolysis. Micromotion between the back of the polyethylene liner and the metallic base plate/tray leads to "backside wear". Backside wear has been claimed to be of greater osteolytic significance than the wear experienced on the front articulating surfaces because of the larger backside contact area and the potentially smaller particles generated, although accurate quantification of backside wear has proven difficult. The relationship between daily physical activity and location specific TKR wear is also not known. We hypothesize that the motion and force profiles inputted to wear simulators must be from multiple daily activities measured from TKR patients in order to accurately reproduce clinically observed wear rates and patterns on both the front and backside of TKRs. We propose three aims to investigate our overall hypothesis. In the first two aims we will demonstrate that more realistic wear is generated using input profiles from TKR patients and from multiple daily activities. In the third aim we will design and validate a new multi-activity wear protocol reflecting true in vivo use. We will use novel technology that uses lanthanide stearates to track polyethylene wear in serum with mass spectrometry. Different elements are used for different TKR interfaces to allow in situ tracking of frontside versus backside wear. Findings will be validated using retrievals with unique gait and activity information. The studies are purposefully limited to cruciate-retaining TKR design with a high market share.