The House Democrats outlined that the metal-on-metal hip implants have tiny metal particles that wear and enter the bloodstream from the friction of the ball and the cup, per the U.S. Food and Drug Administration (FDA). The agency has received over 5,000 complaints in the first six months of 2011, which was more than the agency had received in the prior four years combined.
Kind of interesting that now the congress wants to advocate holding hearings on the Depuy hip recall.
Here is the orignal letter: I suggest glancing through it.
This information came from the Ennis and Ennis site.