| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 94 === The wear patterns of ultra high molecular weight polyethylene (UHMWPE) used in artificial knee joint were studied in this research. A knee joint simulator was used to simulate the vertical load, anterior-posterior translation, flexion-extension and internal-external rotation in a complete walking cycle. Two different contact compressive stresses of 16.5MPa and 9.76MPa were set in this experiment.
The experimental results show that obvious wear print would be observed in anterior area, it was caused by bearing high stress and relative sliding. The wear depth in this area was also deeper than that in other area. Subjected to the higher stress (i.e. 16.5MPa), fatigue cracks occurred in axial section perpendicular to the wear surface of the specimens subjected to 1x106 cycle and 2x106 cycle-tests. Subjected to the compressive stress of 9.76MPa, wear situation of the UHMWPE specimen was mild, and no obvious scrape in anterior area. The total wear depth was smaller, only some perpendicular cracks were observed.
The similar wear patterns were observed on both the clinically
used polyethylene and simulated one, especially on the specimens subjected to higher stress. The wear phenomena of delamination wear、stacks of wear debris and scratched marks on the simulated specimens were similar to those on the clinically used UHMWPE.
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