“…Surface evaluations revealed that dry lubrication resulted in melting of the surface, which caused delamination and polyethylene transfer (Dowson and Harding, 1982; Dumbleton and Shen, 1976; Tetreault and Kennedy, 1989) and led to the high wear rates when the product of pressure and velocity limit of the material was exceeded (Dumbleton and Shen, 1976; Rose et al, 1982; Shen and Dumbleton, 1974). While water lubrication also displayed polyethylene transfer (Cooper et al, 1993; McKellop et al, 1978; Tetreault and Kennedy, 1989), which was not clinically relevant, serum lubrication produced scratches on otherwise burnished surfaces similar to those of retrieved implants (McKellop et al, 1978; Rose et al, 1982; Walker et al, 1996; Wright et al, 1982). Thus, it was established that serum or other protein containing lubrication was required in laboratory tests to facilitate wear mechanisms similar to those in vivo (Ahlroos, 2001; McKellop et al, 1978; Rose et al, 1982; Saikko, 2003; Walker et al, 1996; Wright et al, 1982; Yao et al, 2003).…”