"The friction acting in vivo in the artificial hip joint - what are the tribologically relevant influencing parameters in vivo?"

植入人工髋关节被认为是本世纪最成功的整形外科手术。虽然它对于65-79岁的患者非常成功，10年平均翻修率只有5%，但对于更年轻和更活跃的患者来说，翻修率高出三倍，达到15%。在过去的二十年里，植入物表面、轴承副和手术技术的优化并没有带来任何显著的寿命改善。除了体内的摩擦和由此产生的种植体磨损外，特别是种植体部件的错误定位是失败的潜在原因。活体关节摩擦是影响人工关节置换术成活的多因素。术中在“安全区”内准确定位假体是保证短期和长期生存的重要因素。我们自己的工作表明，术中调整的关节顶板是术后关节摩擦发生在体内的主要关键参数。然而，对所有潜在影响参数的系统和全面调查尚不存在，这些参数是适应和设计摩擦学优化的“安全区”所必需的。为了能够实现这样的生物力学-摩擦学优化，需要对体内摩擦进行更详细的研究。其中，该项目将调查接触力和杯子上的摩擦产生的体内应力与骨盆界面上产生的应力之间的关系。此外，还将系统地研究各种活动对滑动和润滑条件的影响，以及骨盆倾斜对关节和摩擦载荷的影响及其在术后过程中的变化。基于Julius Wolff研究所(夏里特的柏林健康研究所)和生物力学和植入研究实验室(海德堡大学医院)的密切合作，该项目将首次创造一种独特的组合，通过体外、计算机方法和体内测量来系统地分析特定的摩擦参数。

Implantation of an artificial hip joint considered today as the most successful orthopaedic operation of the century. Although it is extraordinarily successful for patients between 65 - 79 years with an average 10-year revision rate of only 5%, the revision rate for younger and more active patients is three times higher with 15%. Optimization of implant surfaces, bearing couples and surgical techniques have not led to any significant improvement in longevity over the last two decades. In addition to the friction acting in vivo and the resultant implant wear, incorrect positioning of the implant components in particular are discussed as potential reasons for failure. The joint friction occurring in vivo is a multifactorial factor for the survival of the artificial joint replacement. Accurate intraoperative positioning of the components within a "safe zone" is an essential factor for the short- but also long-term survival. Our own work has shown that the intraoperatively adjusted joint roofing is a primary key parameter for joint friction occurring postoperatively in vivo. However, a systematic and fully comprehensive investigation of all potentially influencing parameters, which are needed for the adaptation and design of tribologically optimized "safe zones", does not exist yet. In order to be able to realize such a biomechanical-tribological optimization more detailed investigations of the friction in vivo are necessary. Among others, the project will investigate the relationship between the in vivo stress from contact forces and friction on the cup and the resulting stresses in the interface to the pelvis. In addition, the influence of various activities on the sliding and lubricating conditions, as well the influence of the pelvic tilt on the joint and friction loads and its change in the postoperative course will be systematically investigated. Based on the close cooperation of the Julius Wolff Institute (Berlin Institute of Health at Charité) and the Laboratory of Biomechanics and Implant Research (Heidelberg University Hospital), this project will create for the first time the possibility to analyze specific parameter of friction systematically in a unique combination of in vitro and in silico approaches and in vivo measurements.