Tuesday, December 4, 2012

comments from an MD invovled with Cobalt Related issues with his hip

I published this comment but thought it was worth seeing as a primary topic on the blog.

Hi Connie,
Since the Alaska Epi report our first two cases have been detailed in the 12/2010 American JBJS. A more general paper on identifying patients at risk for cobalt poisoning was publish in Alaska Medicine in Summer 2010. These paper are easily found on line. We now have about 25 patients that have required revision of metal-metal hips because of Adverse Reactions to Metal Debris (ARMD), of those six likely have cobaltism. There are now about 14 published case of arthroprosthetic cobaltism. So far the toxic patients have had blood cobalt levels > 14 mcg/Liter. Early symptoms can include mood changes and tinnitus (ringing in the ears), rashes, and being easily winded. Patients with cobalt levels in excess of 20 mcg/Liter have been noted to develop stiffening of the heart on echocardiogram and high frequency deafness, and cognitive decline. Patient with blood cobalt level > 100 have been reported to have developed deafness, blindness, overt heart failure, hypothyroidism or goiter (enlargement of the thyroid gland), and peripheral neuropathy (numbness and weakness in the extremities).

Stephen Tower, M.D.
Stephen Tower, M.D., was injured by the same artificial hip he implanted in patients.
Photo by: Clark James Mishler
If any patient should have gone into a hip replacement fully informed, it was Stephen Tower, M.D., 55, an orthopedic surgeon from Anchorage, Alaska. Instead, he became the victim of another device that was grandfathered onto the market without clinical testing.
In this case, it was an artificial hip introduced in 2005 by DePuy, the orthopedic division of Johnson & Johnson. Called the ASR XL (shown at the top of this page), it was distinctive because both components—the ball at the top of the femur and the socket liner inside the pelvis—were made of chrome-cobalt metal.
The FDA cleared it without clinical testing based on “substantial equivalence” to earlier devices, though such metal-on-metal hips had long been on the agency’s high-priority list for requiring advance clinical trials.
The all-metal hips were supposedly a great advance over hips with the traditional plastic socket liner, Tower recalls. “The main reason hips traditionally failed was because of plastic wear,” he says. “The metal-on-metal hip was being promoted not only commercially but in the medical literature as being a solution for patients like me, who wanted to return to no-holds-barred physical activity.”
By 2006, Tower’s arthritic hip had forced him to give up practically all the outdoor pursuits he had moved to Alaska to enjoy. He had a DePuy ASR XL implanted in May of that year, and “within six weeks I did a double century bike race,” he says. He was so enthusiastic that within 10 months he had put various models of metal-on-metal hips in six of his patients.
But by the time a year had passed, it became clear that something was wrong. His hip was “pretty much constantly painful” and the chromium and cobalt levels in his blood “were notably high,” he says.Then he started noticing other problems, such as disturbed sleep, mood swings and anxiety, hearing loss, visual problems, and tinnitus.
Throughout that period, he says, he repeatedly questioned DePuy engineers, design surgeons, and sales representatives, “and they’d say, ‘Geez, Steve, we haven’t heard of this.’
Tower’s symptoms became so severe at times that he was unable to work. Meanwhile, his research, some of which he has since published in medical journals, was uncovering evidence that metal debris from joint implants can cause what he describes as “profound poisoning.”
After having the hip removed in 2009 and replaced with a new one made of ceramic and plastic, his symptoms have markedly improved.
In August of 2010, DePuy recalled all 93,000 ASR XL hips worldwide after it became clear that the device was failing far more often than average and producing serious injuries. While it’s unclear how many people actually have had to have their artificial hip removed, an article in the British Medical Journal called it “one of the biggest disasters in orthopaedic history.”
Although the hip was invented and manufactured by an American company, the recall occurred because as early as three years previously—even as DePuy’s engineers were assuring Tower that the hip had no problems—regulators in Australia, England, and Wales were noticing serious problems.
They were able to do so because they have national joint registries—a list of every joint implanted—and the ability to track how patients fare with various models. There is no such national registry in the U.S., although Kaiser Permanente has a large private one.
The FDA has a voluntary system whereby doctors, manufacturers, and patients can report problems with medical devices. And though experts estimate that only a fraction of device problems ever get reported, from 2009 through 2011, the agency received 20,518 reports of injuries from metal-on-metal total hip replacements. Of those, 15,137 concerned the now recalled DePuy hip. Many of the remaining complaints concerned several other brands and models that are still on the market in the U.S.
The 2011 Institute of Medicine panel concluded that the FDA’s ability to spot problems is so inadequate that it’s “impossible to confidently draw broad conclusions about the safety and effectiveness of products that are on the market.”

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