Influence of gelatin and bovine serum lubricants on ultra-high molecular weight polyethylene wear debris generated in in vitro simulations

Ultra-high molecular weight polyethylene (UHMWPE) wear debris induced osteo lysis has a major role in the late aseptic loosening and ultimate failure o f total hip replacements (THR). Clinically relevant ill vitro simulations o f wear are essential to predict the osteolytic potential of bearing surface s in artificial hip joints. Newborn calf or bovine serum has been accepted as a boundary lubricant for such in vitro tests, but its biological stabili ty has been questioned. This study compared the wear factors, number of wea r particles and levels of microbial contamination produced in bovine serum and a gelatin-based lubricant. The wear factors produced by the two lubrica nts were not significantly different, however the wear debris morphology pr oduced was substantially different. The bovine serum became contaminated wi th micro-organisms within 28 h, whereas the protein-based lubricant remaine d uncontaminated. The results showed that bovine serum was not a stable boundary lubricant. T hey also showed that although the wear factors for the two solutions were n ot significantly different, the protein-based lubricant was not a suitable alternative to bovine serum because the wear debris produced was not clinic ally relevant.