It has been recognized that severe wear and aseptic loosening caused by polyethylene wear particles were
the main reasons for the failure of metal-on-UHMWPE implants [3]. To avoid polyethylene wear particles
MoM material combinations have attracted more attention in the mid 1980’s due to its high wear
resistance. The long-term survival in some patients encouraged its usage particularly in younger and more
active patients. However in recent years, concerns have arisen regarding high wear of some implant
designs [4, 5], and, in general toxicities of metal wear particles and metal ions that may transport outside
the joint capsule and cause adverse tissue reactions both locally and remotely [6]. Despite the potential
biocompatibility issues associated with metal debris some MoM hip implants have exhibited encouraging
tribological and clinical performance