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How the ASR XL Acetabular System Became “Substantially Equivalent”

By Taylor Lindstrom

A 30-year-old man needs a hip replacement. His surgeon recommends a DePuy ASR XL Acetabular system because its metal-on-metal design is more durable and allows for a more active life. Following the doctor's recommendations, the young man gets the DePuy hip implant. 

Then the hip implant fails. The young man is in extraordinary pain. His revision surgery reveals dead tissue and deteriorated bone, making it extremely difficult for his new implant to take hold. He takes a blood test that reveals extremely elevated levels of cobalt and chromium. He is now hypersensitive to metal and the surgeon warns him he may contract early-onset osteolysis.

The young man blames the surgeon for recommending the ASR XL Acetabular system in the first place? But the surgeon isn't the culprit in this scenario; he made the best recommendation he could for his patient. The surgeon is simply another victim of the real culprit: an FDA approval loophole called "substantial equivalence."

A surgeon has countless medical devices to choose from. In the world of hip implants, he's looking at numerous options. The surgeon naturally wants to give his patients the best implant possible for their situation, so he chooses only FDA-approved devices that have been rigorously tested for safety.

Or so he thinks.

Does an FDA Endorsement Guarantee Hip Implants' Safety?

The FDA has two processes for approving a new medical device: the premarket approval process, and the premarket notification approval process. Similar as their names are, there is a world of difference between those two processes.

In the case of the patients who received an ASR XL Acetabular system, it may have been the difference between an improved quality of life with a working hip implant - or a drastically reduced quality of life with a faulty one.

The premarket notification process is also known as the 510(k) process, and it includes the loophole of " substantial equivalence." The 510(k) process allows a product to go directly to market without full clinical testing if the manufacturer claims the medical device is "substantially equivalent" to another device already on the market.

According to FDA documents, a substantially equivalent product is one that is created for the same intended use as the previously approved products; has the same design, materials and technology; and raises no new concerns about safety or effectiveness.

Substantial equivalence was designed to prevent the 2-3 year waiting period for testing. If one hip implant is so similar to another device that it could be expected to get the same test results, what was the point of testing it?

One might argue "safety," but one would be naive to do so. Medical device companies pushed for the substantial equivalence loophole for an entirely different and far less altrustic reason: profits. Every year spent in testing is a year that hip implant isn't on the market earning money for the company.

A Pyramid Built on Sand

For Johnson & Johnson and its subsidiary DePuy, the priority was on products, not patients. They claimed the ASR XL Acetabular System was "substantially equivalent" to no less than three other devices already on the market that had been tested for safety.

Every part of that statement would prove to be inaccurate.

Companies are allowed to claim that their new product is substantially equivalent to more than one other product.  For example, since they have to show that they have the same materials and technology as a previously approved product, a company might show that they used the same materials as one product and the same technology as another. 

For the ASR XL Acetabular system's 510(k) application, DePuy cited three different previously approved products saying that the ASR system was "substantially equivalent"-at least in part-to all three. 

By this argument, you could get a safety approval from the FDA for a flying car with submarine without ever testing it - after all, it is "substantially equivalent" - at least in part - to an airplane, a car, and a submarine. What on earth would be the point in testing it again when the basic principles have already been proven safe?

The loophole gets even more absurd: companies are allowed to base their claims of "substantial equivalence" on products that were approved under the same 510(k) process. 

One of the devices DuPuy used was approved with one device-that had been approved through another device-that had been approved through a third device-that was approved because it was substantially equivalent to a product grandfathered into the system prior to 1976.

Essentially, DePuy was claiming that their product was substantially equivalent to hip replacements manufactured before the FDA was ever in place.

Not a single hip implant in this chain of FDA was ever subjected to clinical trials before it was allowed to go to market. Even if it had been, it seems laughable that a hip implant "substantially equivalent" to a series of pre-1976 implant could ever make it through the FDA. Has technology developed so slowly that the best implants on the market are based on designs from 40 years ago?

Put it into perspective: the ASR XL Acetabular system was marketed to younger people who needed a longer-lasting, more durable hip replacement. That means many of the recipients got a hip implant based on a design older than they were.

Only 10% of applications submitted under the 510(k) process are ever returned with a request for clinical trials. That means that 90% of the Class III hip implants available today were never tested in a clinical setting before being marketed to the public.

It's a wonder there haven't been more problems with these hip implants. How many of us would willingly submit to the medical procedures of 40 years ago?

Testing the DePuy Hip Implant Takes a Backdoor to Profits

Had thorough clinical testing been done, it would have become clear long before the product went to market that the ASR XL Acetabular system had a revision rate of at least 15% and possibly more, not to mention a much higher rate of metallosis, metal poisoning, bone deterioration, and tissue damage.

Had DuPuy gone through the more rigorous PMA process with the FDA, it's likely the ASR system would never have been sold to the public.

But then again, that was probably why DePuy didn't go through the more rigorous process. The 510(k) process and substantial equivalence meant that DePuy could start making profits off their hip implants much more quickly. Why risk losing the profits just because the device can't be proven safe?

While we acknowledge that companies need to make profits, companies who make medical devices such hip implants must be driven by consumer safety above all else. Willingly causing pain and suffering to thousands of people in exchange for a payoff makes DePuy "substantially equivalent" to a hired thug.

It's a harsh comparison - but one that holds up much better under scrutiny than the ASR XL Acetabular System.

If you're among those who received a DePuy hip implant, we'd like to help  answer any questions you may have, both medical and legal. DePuy didn't care about your safety enough to compromise their profits; we do.

Contact Us

If you think you have a DePuy hip implant and would like to know more about the case, give our offices a call at 1-800-677-7095. We have people standing by to answer your questions and explain how we can help.

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