Faulty DePuy Artificial Hip Points to Broken Implant System - NYTimes.com

As I am wont to say about drugs - post-approval is Phase IV: the mass, poorly controlled, human experiment stage, so with devices like hip implants which, if they are "substantially equivalent" to devices already on the market, or make only minor changes, are subject to minimal FDA review.  Followed, of course, by maximum marketing.
“You are basically testing these devices in an uncontrolled way on a large number of people,” said Dr. Sidney M. Wolfe, the director of the Public Citizen’s Health Research Group and a longtime F.D.A. critic.
Faulty DePuy Artificial Hip Points to Broken Implant System - NYTimes.com