Daily Activity of TKR Patients as Input for Wear Testing

描述（由申请人提供）：全膝关节置换术（TKR）在缓解膝关节损伤和/或疾病患者疼痛和改善功能方面越来越成功。尽管取得了这一成功，但由于磨损导致的膝关节植入物失效仍然是一个突出的问题，通常导致翻修手术。模拟膝关节的运动和载荷的模拟器被广泛用于评估和改进未来的膝关节假体设计。然而，目前用于模拟的输入数据是基于水平行走过程中的典型正常受试者，尽管有证据表明超过75%的全膝关节假体患者行走异常。日常活动水平、实际膝关节负荷和这些活动期间的膝关节运动轮廓，以及它们对TKR患者假体磨损的影响在很大程度上是未知的。为了为临床前磨损测试提供准确的输入数据，我们将测试以下假设：TKR患者在日常体力活动中表现出与膝关节模拟器中目前使用的不同的运动和载荷曲线。我们的初步数据表明，在瑞士TKR人群中，只有10%的日常活动用于“水平行走”。此外，这些患者的膝关节最常穿过30度屈曲水平，而模拟器最常穿过10度水平。该数据突出了患者家中和社区中膝关节功能使用与当前用作关节模拟器输入数据之间的差异。我们将在植入Miller-Galante（MG）或Miller-Galante II型（MGII）假体的TKR受试者中检验我们的假设。受试者将佩戴活动监测器一天，该监测器将提供全天活动水平和膝关节活动范围的数据。受试者还将参与运动分析（点簇技术），这将提供这些日常活动期间膝关节3-D运动的更准确测量。基于运动实验室中获得的体内运动学和动力学数据，我们将使用人工膝关节的数学模型计算接触力。

DESCRIPTION (provided by applicant): Total knee replacement (TKR) has shown increasing success in relieving pain and improving function for patients suffering from knee injury and/or disease. Despite this success, knee implant failure due to wear is still a prominent problem usually leading to revision surgery. Simulators mimicking the motions and loads of knee joints are widely used to evaluate and improve future designs of knee prostheses. However, the input data currently used for simulation is based on typical normal subjects during level walking although there is evidence that more than 75% of patients with a total knee prosthesis walk abnormally. Daily activity levels, realistic knee joint loads and knee motion profiles during these activities, as well as their impact on the wear of the prosthesis for TKR patients are largely unknown. In order to provide accurate input data for preclinical wear testing, we will test the hypothesis that patients with a TKR demonstrate a different motion and load profile during daily physical activities than what is currently used in knee joint simulators. Our preliminary data indicate that in a Swiss TKR population, only 10% of daily activities was spent on "level walking". In addition, the knee joint of these patients most often crossed the 30 degree flexion level, in contrast with the simulator, which crosses the 10 degree level most frequently. This data highlights the discrepancies found between the functional use of the knee joint in the patient's home and community and what is currently used as input data for joint simulators. We will test our hypothesis in TKR subjects who have a Miller-Galante (MG) or Miller-Galante type II (MGII) prosthesis. Subjects will wear an activity monitor for one day which will provide data on their activity level and knee range of motion throughout the day. Subjects will also participate in motion analysis (point cluster technique) which will provide more accurate measurements of the 3-D movement of the knee during these daily activities. Based on the kinematic and kinetic in vivo data derived in the motion laboratory, we will calculate contact forces using a mathematical model of the artificial knee.