Fig. 5.

Through-thickness total wear penetration rate versus in vivo duration is shown for the Sigma^® fixed bearing inserts, including those in rough Ti trays with 4-Mrad gamma-irradiated and barrier-packaged material (Ti 4 MR GB) and those in polished CoCr trays with (1) 4-Mrad gamma-irradiated and barrier-packaged material (CoCr 4 MR GB) and (2) 5-Mrad gamma-irradiated and gas plasma-sterilized material (CoCr 5 MR XL). Fixed bearings showed an increasing wear rate with increasing in vivo duration.