A Model on the Motion of Wear Particles in the Synovial Fluid of an Artificial Hip Joint

Improvements in surgical procedures, installation techniques and properties of materials have resulted in a remarkable reduction in the failure of artificial hip joints (AHJ) due to infection. However, the durability of these replacements is greatly limited by premature osteolysis and eventual joint loosening, caused by macrophage activity in response to the release of submicron particles of ultra-high molecular weight polyethylene (UHMWPE) cup material [1–4]. The wear debris is mainly due to wear between the bearing surfaces, and these wear rates are known to be accelerated by the third body action of polymethylmethacrylate (PMMA) bone cement particles and metallic fragments of the femoral head material scattered within the synovial fluid lubricant [5]. This study is focused on development of a model that simulates the motion of UHMWPE particles in the synovial fluid between the AHJ bearing surfaces during articulation.