Abstract
The purpose of this study was to examine influences of the prolonged stance phase; long stationary loading duration at stance phase, on wear characteristics of an ultra-high molecular weight polyethylene (UHMWPE) cup in an artificial hip joint with a cobalt-chromium-molybdenum (Co-Cr-Mo) alloy ball. Lubricant was a water-based liquid, and it contained principal constituents in synovial fluid. The wear of UHMWPE cup with the prolonged stance phase (interruption cycle) was lower than that without the prolonged stance phase (sequence cycle). Adhesives material on the bearing surface of Co-Cr-Mo alloy ball was clearly observed in the interruption cycle. Stationary loading without sliding motion such as the prolonged stance phase might cause the exfoliation of adsorbed film of the synovia constituents on the bearing surface to increase. That lead to the transferred film artifacts, which reduced the wear of UHMWPE cup.
