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45万例手术，全膝关节置换术（TKR）已成为一种常见的外科手术，可减轻患病或创伤膝关节的疼痛并增加功能活动能力。限制tkr使用寿命的主要因素是聚乙烯胫骨衬垫的磨损。预期寿命和体重的增加，以及年轻患者接受TKR手术的趋势，将对未来的设备提出更高的要求。临床前耐力测试已经成为在种植体开发过程中预测新设备机械性能的标准程序。这些测试程序遵循从测试到成功的策略，这需要从日常使用的负载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并没有模拟植入十字交叉保留膝关节假体患者的步态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，但其他日常体育活动通常会产生更高的胫骨负荷，更大的假肢运动，以及比步行更有害的交叉剪切。事实上，测试部件的磨损特征与体内磨损不匹配，无论是磨损疤痕的大小和形状，还是磨损形态。tkr的正面、内侧和外侧承载面并不是导致磨损和骨溶解的唯一表面。聚乙烯衬垫背面与金属底板/托盘之间的微运动导致“背面磨损”。由于后部接触面积更大，产生的颗粒可能更小，因此后部磨损被认为比前关节面磨损具有更大的溶骨意义，尽管事实证明，对后部磨损的准确量化是困难的。日常体力活动与特定位置的TKR佩戴之间的关系也不清楚。我们假设输入到磨损模拟器的运动和力轮廓必须来自TKR患者的多次日常活动测量，以便准确地重现临床观察到的TKR前后的磨损率和模式。我们提出三个目标来调查我们的总体假设。在前两个目标中，我们将展示使用来自TKR患者和多种日常活动的输入数据生成更真实的磨损。在第三个目标中，我们将设计和验证一种反映真实体内使用的新的多活动穿戴方案。我们将使用新技术，使用镧系硬脂酸盐质谱追踪血清中的聚乙烯磨损。不同的TKR接口使用不同的元件，以允许现场跟踪正面和背面磨损。研究结果将通过独特的步态和活动信息进行验证。这些研究有目的地局限于具有高市场份额的十字架保留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.