Steven Kurtz, biomedical engineer and director of the Implant Research Center at Drexel University, is the proud owner of an unusual collection of more than 7,000 artificial knees, hips, and other implants from around the U.S. He receives boxes of discarded devices from 15 hospitals in eight states, all in the name of making artificial implant technology better.
“We study the tough things that happen to good implants,” said Kurtz.
Kurtz has found that the most common reasons for the failure of joint replacement are infection, a loosening of the device, or dislocation, specifically in hip replacements. It’s less common for the material in the device to fail – unless it is a metal-on-metal hip implant, such as the designs made by DePuy Orthopaedics.
William M. Mihalko, a professor of orthopedics at the University of Tennessee, is a supporter of Kurtz’s research and efforts, saying it could help “avoid implant design variables that are problematic or raise the red flag about an issue sooner rather than later.”
One study Kurtz performed allowed him to conclude that cobalt chrome alloy produce more corrosion than hips made with plastic or ceramic heads. He further concluded that the stem portion of the metal heads had increased modularity that resulted in “fretting,” noticing tiny scratches from the back-and-forth motion of normal wear.
The complaints claim that when the metal-on-metal parts rub together, debris flakes off, polluting the bloodstream and damaging surrounding tissue.
In many cases, patients implanted with metal-on-metal hip replacements have required revision surgery and/or replacement. The device manufacturing giant sold 150,000 of the metal artificial hip implants in the 2000s, allegedly with knowledge of the design’s risks.