Following the recalls of metal-on-metal hip replacements, most of us are aware of the potential hazards related to the implant parts which are constructed of cobalt and chromium. Metal poisoning can occur when the metal components rub against one another, causing tiny metal ions to shear away and enter the surrounding tissues and/or the bloodstream. Many recipients of all-metal hip implants—like the recalled Stryker Rejuvenate and ABGII—have ended up with serious health issues from the toxic effects of cobalt and chromium in the body...

Patients with Stryker ABGII or Rejuvenate hip implants could see a wide variance between the cobalt and chromium levels with the cobalt levels being considerably more elevated. The probable reason for the difference in these numbers is that the wear in the Rejuvenate and ABGII hip implants does not come from the cup and ball portion of the joint rather it comes from the stem and neck. The design of these Stryker devices implements a Morse taper between the stem and the neck.  The Morse taper is a slightly angular junction which the physician hammers into the stem until it is snug, then hammers again so it will lock tightly.