Improved friction and wear performance in polymeric components of orthopaedic bearings.

每年有近2.5万加拿大人和全球60万人植入人工膝关节。这些设备通常使用由金属(钴铬)和塑料(超高相对分子质量聚乙烯)制成的特殊部件进行设计。它们是治疗严重退行性关节疾病的首选药物，现在正被植入活跃的患者身上，其中一些人只有45岁。因此，越来越需要提高它们的耐用性，特别是在塑料部件中的磨损方面。尽管用于髋关节的聚乙烯的设计有所改进，但对于膝盖等高应力关节来说，情况并非如此。该项目研究了一种处理塑料材料表面以减少磨损的新方法。人们认为，聚乙烯表面的小凹痕或酒窝会携带关节液体，这将有助于润滑关节，并减少塑料本身的应力。随着应力的降低，塑料磨损应该会减少。人类软骨形态具有直径小于40微米、深度小于15微米的自然凹陷，可以作为表面纹理的模型。这种几何形状将使用女王学院的专门加工设施在聚乙烯表面重现，并进行测试，以确定这是否可以减少实验室样品的摩擦和磨损。如果成功，将在磨损模拟器中对人造关节的纹理过程进行评估，该模拟器再现现实生活中发生的载荷和运动。其目的是通过提高人工膝关节的耐用性来减少更换磨损的人工膝盖的需求，使其耐用性超过目前预期的15年，并为越来越多的老年人提供远远超过现在可能的终身活动。

Nearly 25,000 Canadians and 600,000 worldwide are implanted with an artificial knee each year. These devices are most often designed using specialized components made of metal (cobalt chrome) and plastic (ultrahigh molecular weight polyethylene). They are the treatment of choice for severe degenerative joint disease, and they are now being implanted in active patients, some as young as 45. As a result, there is an increased need to improve their durability, particularly with respect to wear in the plastic component. While there have been improvements in the design of polyethylene for use in hips, this has not been the case for highly stressed joints such as the knee. This project examines a novel way of treating the plastic material surface to reduce wear. It is thought that small indentations, or dimples, in the polyethylene surface will entrain joint fluid that will help lubricate the joint and also reduce the stress on the plastic itself. With reduced stress, reduced plastic wear should result. It is reasoned that human cartilage morphology, which has naturally occurring dimples less than 40 micrometers in diameter and 15 micrometers deep, could be used as a model for the surface texture. This geometry will be reproduced on polyethylene surfaces using specialized processing facilities at Queen's and tested to determine if this can reduce friction and wear in laboratory specimens. If successful, the texturing process will be evaluated on artificial joints in a wear simulator that reproduces loads and motion that occur in real life. The aim is to reduce the need to replace worn out artificial knees by improving their durability beyond the 15 years currently expected and provide a growing number of aging adults with a lifetime of activity well past what is now possible.