WEAR OF ULTRA-HIGH-MOLECULAR-WEIGHT POLYETHYLENE AGAINST DAMAGED AND UNDAMAGED STAINLESS-STEEL AND DIAMOND-LIKE CARBON-COATED COUNTERFACES

The wear of ultra-high molecular weight polyethylene (UHMWPE) in artif icial joints and the resulting wear debris-induced osteolysis remains a major clinical concern in the orthopaedic sector. Third-body damage of metallic femoral heads is often cited as a cause of accelerated pol yethylene wear, and the use of ceramic femoral heads in the hip is gai ning increasing favour. In the knee prostheses and for smaller diamete r femoral heads, the application of hard surface coatings, such as dia mond-like carbon, is receiving considerable attention. However, to dat e, there has been little or no investigation of the tribology of these coatings in simulated biological environments. In this study, diamond -like carbon (DLC) has been compared to stainless steel in its undamag ed form and following simulated third-body damage. The wear of UHMWPE was found to be similar when sliding against undamaged DLC and stainle ss steel counterfaces. DLC was found to be much more damage resistant than DLC. Under test conditions that simulate third-body damage to the femoral head, the wear of UHMWPE was seven times lower against DLC th an against stainless steel (P < 0.05). The study shows DLC has conside rable potential as a femoral bearing surface in artificial joints.