Study on Biotribological Behavior of the Combined Joint of CoCrMo and UHMWPE/BHA Composite in a Hip Joint Simulator

UHMWPE composites reinforced with Bovine Bone Hydroxyapatite (BHA) in different contents were prepared by heat pressing formation method. A hip joint wear simulator was used to investigate the biotribological behavior of UHMWPE/BHA composite acetabular cups against CoCrMo alloy femoral heads in bovine synovia lubrication at 37 ±1 °C. It was found that the addition of BHA powder to UHMWPE can improve the hardness and creep modulus of UHMWPE/BHA composites, and decrease their wear rates under bovine synovia lubrication. When the content of BHA filler particles was up to 30 wt%, UHMWPE/BHA composites demonstrated the well design performances of the surface and biotribological properties. Fatigue, ploughing and slight adhesive wear were the main wear mechanisms for UHMWPE and its composites. In addition, the sizes of wear particles became larger with an increase in BHA powder addition. These results suggest that BHA filler is a desirable component to increase the wear resistance of UHMWPE/BHA composites for biomedical applications.