This work aimed at scrutinizing the tribological performance of UHMWPE articulated against stainless steel and zirconia reinforced alumina, under polymer delamination scenario. Linear reciprocating tests were performed under bovine calf serum lubrication. The worn surfaces were analyzed by 3D profilometry and microscopy. Performed microanalyses revealed that scatter in wear mechanisms and in friction behavior was affected by particular events at the micro-contact: in poly-metal tribosystems, micro-spots in the metal have triggered abrasion in the polymer besides delamination, and led to raise friction level; in poly-ceramic tribosystems, microtribofilm formation in the ceramic was the responsible for the same deviations. The identified micro-events normally go unnoticed in standard analyses of articulated implants, but disclosed pathways to make improvements in the specific pair.