Tribological optimisation of hip endoprostheses by developing an artificial synovial fluid and a novel hip tribometer

在德国，每年大约有20万人选择人工髋关节，用人工髋关节代替人工髋关节。该手术是骨科手术的标准程序之一。在运动过程中，髋关节假体暴露在大负荷下，特别是股骨头和髋臼之间的滑动配对，因此也容易产生严重的磨损。两个摩擦伙伴的机械工作产生了相当大的材料磨损，这可能导致周围组织的炎症和随后的假体松动，这需要更换。然而，髋关节假体的翻修手术比第一次植入更困难，因为假体在骨内的固定比第一次手术更困难。这是由于人工关节的金属和塑料磨损引起的炎症，导致骨物质减少。健康髋关节的润滑液是由滑液膜产生的滑液。植入假体和关节炎症会改变滑膜液的成分，导致滑膜液的润滑性降低。在本项目中，将详细检查假体植入前后滑液的性质和化学成分。在这个项目中获得的结果的帮助下，将产生一种人工滑液，满足对种植体的最佳润滑要求。为了研究其摩擦学特性，将开发一种新的测试台，该测试台设计为股球/窝测试台，可以直接测量测试配对上的摩擦，同时考虑到更现实的关节样润滑剂量（约为1）。3 - 10毫升)。这样就可以确定每种材料配对的最佳润滑液，检查人工和健康滑液之间的相似性，以及对润滑性能的积极影响因素。目的是优化一种合成滑液，以便将来在髋关节植入患者中使用。

In Germany, around 200,000 people opt for an artificial hip each year and have their hip joint replaced by an endoprosthesis. The operation is one of the standard procedures in orthopedic surgery. The hip prosthesis is exposed to heavy loads during movement, especially the sliding pairing between the femoral head and the acetabulum and is therefore also subject to heavy wear generation. The mechanical work of the two friction partners creates considerable abrasion of material, which can lead to inflammation of the surrounding tissue and subsequent loosening of the endoprosthesis which than requires a replacement. However, a revision surgery of the hip prosthesis is more difficult than the first implantation, because the fixation of the endoprosthesis in the bone is more difficult compared to the first operation. The cause of this is the inflammation caused by the metal and plastic wear from the artificial joint, which leads to a decrease in the bone substance. The lubricating fluid of a healthy hip joint is the synovial fluid produced by the synovial membrane. Implantation of an endoprosthesis and joint inflammation change the composition of this synovial fluid, which leads to a reduced lubricity of the fluid. In the present project, the properties and chemical composition of the synovial fluid before and after prosthesis implantation will be examined in detail. With the help of the results obtained in this project, an artificial synovial fluid will be produced that meets the requirements for optimal lubrication of the implant. To investigate the tribological properties, a new test stand will be developed, which is designed as a femoral ball / socket test stand and can measure the friction directly on the test pairing, taking into account a more realistic joint-like amount of lubricant (approx. 3-10 ml). This makes it possible to identify an optimal lubricating fluid for each material pairing, to check the similarity between artificial and healthy synovial fluid, and the positive influencing factors on the lubricating properties. The aim is to optimize a synthetic synovial fluid for the use in the patient with hip implants in the future.