Comparative study of the wear of UHMWPE with zirconia ceramic and stainless steel femoral heads in artificial hip joints.

The wear of ultra high molecular weight polyethylene (UHMWPE) when sliding against zirconia ceramic and stainless steel counterfaces has been compared in a pin-on-plate reciprocator and in a hip joint simulator. A lower wear factor was found for the UHMWPE when sliding on the zirconia ceramic counterfaces in the pin-on-plate tests. In the hip joint simulator test, the acetabular cups articulating on zirconia heads showed consistently lower volume changes than the cups articulating on stainless steel heads. The higher volume changes found with the stainless steel heads were associated with an increased roughness of the femoral heads during the tests. This roughening was caused by the adherence of a rough polymer transfer film.