Saikko V O
Laboratory of Machine Design, Helsinki University of Technology, Finland.
Proc Inst Mech Eng H. 1996;210(3):175-85. doi: 10.1243/PIME_PROC_1996_210_410_02.
A three-axial, single-station hip joint simulator was designed and built for wear and friction studies on total hip prostheses. The design of the apparatus is described in detail. Continuous level walking is simulated. All three motion components, flexion-extension, abduction-adduction and internal-external rotation, are included. The motions are implemented electromechanically and the uniaxial load pneumatically. The load is measured continuously. For accurate measurement of wear, the apparatus has a loaded control joint, which also renders both the test and control joints self-centering, as they are loaded in series. The frictional torque of the test joint can be measured continuously throughout the wear test, which is an exceptional feature. Four tests of five million cycles each were completed using 32 mm diameter Co-Cr-Mo femoral heads and 5.6 mm thick, metal-backed, ultra-high molecular weight polyethylene acetabular cups as test specimens. Their wear and friction behaviour is described and discussed in relation to previous simulator studies and clinical observations. The lubricant was distilled water, maintained at body temperature. The wear of the cups was measured gravimetrically at intervals. The average wear rate was 3.9 mg/one million cycles, corresponding to 0.03 mm/year, and the average coefficient of friction was 0.01.
设计并制造了一种三轴单站髋关节模拟器，用于全髋关节假体的磨损和摩擦研究。详细描述了该装置的设计。模拟连续水平行走。包括屈伸、外展内收和内外旋转这三个运动分量。运动通过机电方式实现，单轴载荷通过气动方式施加。载荷进行连续测量。为了精确测量磨损，该装置有一个加载控制关节，由于测试关节和控制关节串联加载，这也使它们都能自动对中。在整个磨损试验过程中，可以连续测量测试关节的摩擦扭矩，这是一个独特的特点。使用直径32毫米的钴铬钼股骨头和5.6毫米厚的金属背衬超高分子量聚乙烯髋臼杯作为测试样本，完成了四次每次五百万周期的测试。结合先前的模拟器研究和临床观察，对它们的磨损和摩擦行为进行了描述和讨论。润滑剂为保持体温的蒸馏水。定期通过重量法测量髋臼杯的磨损。平均磨损率为3.9毫克/百万周期，相当于0.03毫米/年，平均摩擦系数为0.01。
