Chromium and Cobalt Hip Poisoning in Stryker Hip Implants

Submitted by: Daniel Nigh

When Stryker Orthopaedics introduced its innovative Rejuvenate & ABG II Modular-Neck Hip Stems back in 2010, it was hailed as the greatest invention since the artificial hip implant. Two years later, the company issued a voluntary recall, and the product is now at the center of growing litigation.

The Stryker product is not a “Metal on Metal” (MoM) hip implant in the sense that a metal ball is inserted into a prosthetic metal hip socket. It is actually a series of interchangeable parts that makes it easier for surgeons to tailor the device for a specific patient’s needs.  It is, however made from similar materials – namely, titanium, cobalt and chromium.

Medical researchers are still not sure about all the effects attributed to heavy metal poisoning, such as organ damage (specifically the brain, heart, liver and kidney). However, physicians who have wound up performing “revision surgeries” (in which these devices are removed) have found a wide range of “adverse effects” that includes dead bone and tissue, muscle damage and what are known as “pseudotumors” ( an enlarged mass of tissue that looks like a cancerous tumor, but is the result of inflammation or fluid build-up).

Here is the question: if it was known that microscopic metal particles have a tendency to flake off into the bloodstream of patients who have MoM hip implants, how was it that nobody thought something similar would not happen with the Stryker device? Shouldn’t it have been subject to more thorough testing before it was made available to patients and their doctors?

Apparently not – at least, the fine folks at the U.S. Food and Drug Administration (FDA) didn’t think so. Stryker executives were able to convince the FDA that their new product was similar to a device that had already been approved. The similarity was enough to qualify the the system for expedited approval through the 501(k) Clearance process (click the link to learn more).

The advocacy group Public Citizen has pointed out that 501(k) has been ineffective at preventing harmful products from being marketed, and many consumer advocate groups have been calling for major changes in the law. There have been a few half-hearted attempts a reform in Congress – but since it’s a quick and inexpensive way for the large, powerful medical device makers to get their products on to the market quickly without have to go through all the bother of excessive testing and trials, and since most of Congress is bought and paid for by corporate money, there has been no serious movement in that direction.

In the meantime, while the Institute of Medicare has called on the FDA to abandon the 501(k) Clearance process, a 2011 study from Northwestern University and the Institute of Health Technology Studies has state that the process is too stringent and should be streamlined even further. Approximately 47,000 medical devices have been approved through 501(k) Clearance since it was introduced in the 1970s – amounting to about 90% of all new medical devices that have come on to the market since that time.

Sources

N/A. “Study Calls for Changes to FDA 501(k) Medical Device Sales Clearance Process.” MedReps.com, 10 October 2011. Available at http://www.medreps.com/medical-sales-news/study-calls-for-changes-to-fda…(k)-medical-device-sales-clearance-process-/

Learn more about Depuy Hip and Stryker Hip Recall