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Medical Device Expert Explains DePuy Hip Failure

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Miami, FL"Most Americans who have a DePuy ASR hip implant are under the impression that the metal-on-metal medical device has been clinically tested and approved but it hasn't been," says medical device expert Lana Keeton. "The DePuy ASR hip implant, along with a number of other models, has only been cleared by the FDA."

Keeton has been working in the steel business for over 30 years and she is an expert in the field. "Steelmaking is very process specific and the body is a hostile environment for metal," she says. "All metal is susceptible to corrosion and moisture is its worst enemy, no matter where it is used.

"Most Americans are not aware that the FDA has more than one pathway for medical devices to go to market. They believe hip implants are approved and are safe and effective, but they are not…they are simply cleared for sale into the marketplace."

What does "cleared" mean? Keeton says there are two FDA pathways to be able to sell a medical device:

1. The 510(k) pre-market notification clearance process. There is no proof of safety or efficacy required for most Class I or Class II and even some Class III devices. This 510(k) has been under review by the Institute of Medicine (IOM) and an internal working group at the FDA for over a year now. Some changes are in the process of implementation now by the FDA, and the IOM will be coming out this summer with their recommendations to make this process safer.

2. The FDA Pre-market approval (PMA). This process requires human clinical trials to prove safety and efficacy of the drug or device.

Keeton has a wealth of knowledge about steel and the physical and chemical properties of metals. "I have toured more steel mills and steel manufacturers than I want to remember, and I know what works and what doesn't—I understand how the smallest change in the steelmaking process can impact the final product," she explains.

"I look at the entire process, from steelmaking to surgical implantation and the way the body impacts the device," says Keeton, "and I don't think anyone is looking at the big picture, including the FDA." She believes the FDA is underfunded, understaffed and doesn't have a strong enough regulatory authority. "They are dependent on industry to give them all pertinent information on medical devices and for user fees," she adds.

"The most important thing to consider is that these medical devices, such as the DePuy ASR hip implant, are cleared through a process not requiring testing in human clinical trials. As it stands now, an uninformed patient goes to an accredited hospital, to a licensed doctor who implants an FDA-cleared device and they believe the implant is proven safe, but that is just not true." People with the implants are the clinical trial and when the serious harm becomes apparent, the FDA begins to question why. (More than 90,000 DePuy ASR metal-on-metal hips have been implanted worldwide, and those 90,000 patients were the human clinical trial.)

"Steel has to be in the right environment to perform as intended and the steelmaking process may or may not be correct for what they are doing," Keeton says. "These steel alloys are sometimes tested in simulated human body fluids. And sometimes they are tested in animals. But, in addition to not being human body fluids, animals have four legs so how realistically can you test for wear?

"The manufacturer represents the DePuy hip implant as bio-compatible and it may meet some standards for bio-compatibility but it doesn't mean that it performs as intended in the human body. Anyone who really studies the process will reach the same conclusion: The body fluids are hostile to metal and not reproducible in an animal model."

What are the manufacturers thinking? Keeton says that device makers looking for new markets found young people who will need hip implants for a longer period of time. The metal-on-metal (MOM) was born. But when these untested devices fail, companies frequently make slight revisions in the product and re-apply to the FDA, which once again clears an unproven, potentially unsafe medical device.

"In a nutshell, the metal-on-metal DePuy ASR surgical implant is made from cobalt, chromium and molybdenum. There are typically two forms of the CoCrMo alloy; one is cast and the other is wrought. The wrought is stronger than the cast but the shape of the implant determines whether it is cast or wrought. It is so complicated. And heat changes the microstructure—it is extremely difficult, and even in the best of circumstances of the steelmaking process, there is a 1-2 percent rejection rate."

Keeton also explains in simpler terms. "You bake a cake one day and it comes out of the oven perfect. A few days later, you bake another cake with the same recipe and it comes out flat. It's the same with steel: the metal is so tolerance-specific, from one heat to the next there could be a problem with the quality, in addition to the original design defects.

"The question now isn't if the implants will fail, but when they will fail, so patients have to live with that anxiety. Generally, hip implants are made to have a relatively long life span. The manufacturers saw a need for the metal-on-metal hip implant for young and active people and created the MOM to supposedly last longer than the other designs, but instead it has a shorter life span."

So where does this leave the patient who has recently had a DePuy hip implant and what, if anything, is the FDA doing about hip implants?

"The FDA is not getting all the information in order to truly assess the post-market safety of these products," says Keeton, "but last week the FDA required 21 manufacturers, including DePuy, to start post-market studies of hip implants. Instead of having thousands of injured patients out there, human clinical trials should have been completed prior to implanting any hip replacement into anyone."

As for Lana Keeton, she designs discovery based on her steel-manufacturing expertise knowledge of physical and chemical properties of metal and legal experience, applying the facts to the law in new ways so attorneys will have better tools to win for their clients in the lawsuits against medical device manufacturers.

With thousands of injured hip implant patients, she expects to be working in a consulting capacity for an increasing number of DePuy ASR hip implant lawsuits for seriously harmed patients. Keeton says she would rather these people were not injured and her steel expertise was only needed for products not used in humans.

Visit Lana Keeton's Web site here.


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