Auger D D, Dowson D, Fisher J
Department of Mechanical Engineering, University of Leeds.
Proc Inst Mech Eng H. 1995;209(2):83-91. doi: 10.1243/PIME_PROC_1995_209_324_02.
Cushion knee prostheses have been designed and constructed to produce larger initial contact areas and thicker theoretical film thicknesses than a conventional UHMWPE (ultra-high molecular weight polyethylene) joint. The compliant bearing had a flat tibial component which imposed fewer biomechanical constraints and allowed greater range of movement. Wear tests were performed in a knee joint simulator and creep tests were carried out in a servo-hydraulic apparatus. Various failure modes of cushion joints that require further study were identified. However, the results showed that adequate durability was achieved from a 20 MPa polyurethane material in joint simulating tests carried out over 0.5, 1.0 and 5.0 million cycles. Most importantly, during these tests, no detectable wear debris was generated. It is believed that this is the first time that the full potential of cushion bearings has been demonstrated in a joint simulator over periods corresponding to about five years of service in vivo.
缓冲型膝关节假体的设计和构造旨在产生比传统超高分子量聚乙烯（UHMWPE）关节更大的初始接触面积和更厚的理论膜厚。顺应性轴承的胫骨部件是平的，施加的生物力学约束较少，允许更大的运动范围。在膝关节模拟器中进行了磨损测试，并在伺服液压装置中进行了蠕变测试。确定了缓冲关节需要进一步研究的各种失效模式。然而，结果表明，在超过50万、100万和500万次循环的关节模拟试验中，20兆帕的聚氨酯材料实现了足够的耐久性。最重要的是，在这些测试中，没有产生可检测到的磨损碎片。据信，这是首次在关节模拟器中展示缓冲轴承在相当于体内约五年使用期的时间段内的全部潜力。
