One night, Janice Tower found her “very caring, giving, honest” husband trashing a hotel room using pens and Sharpies to write all over every surface he could and after, soap to write on the bathroom mirror. Leading up to this moment Dr. Stephen Tower, an orthopaedic surgeon much adored by his patients, had been experiencing a tremor in his non-dominant hand, ringing in his ears and found that he repeated himself a lot. The diagnosis: metal poisoning from a hip replacement.
As an avid cyclist, the metal-on-metal (MoM) DePuy ASR hip enticed him because MoM was
advertised to be more resistant to wear and tear - ideal for athletic people. As far as he was concerned, this newly innovated hip replacement was safe and his best chance of returning to intense cycling. A metal-on-metal hip replacement is typically made of a ball and socket composed of an alloy of chromium and cobalt. When the joint is being used the two surfaces rub against each other and result in metal ions invading the surrounding tissue and entering the bloodstream. While this also happens with metal-on-plastic/polyethylene joints, the potential for harm is much worse when two surfaces are shedding these metal ions as opposed to only one.
After his psychological breakdown, he checked his blood and urine and found that the levels of cobalt in his blood were 100 times more than they should be. Cobalt is found in the body at minuscule amounts as part of vitamin B12 essential for erythropoiesis (making red blood cells) and maintaining a healthy nervous system, but heavy metals in large amounts (~7 micro-litres) disrupt the body’s metabolic processes in two ways. The first is that they accumulate and disrupt vital organs, and the second is that they interfere with the biological function of vital minerals (such as iron in the heme molecule) by displacing them. This displacement deactivates enzyme systems or changes important protein structures. Dr. Tower knew that he had to replace the hip and opted for a ceramic-on plastic. Within a month, all of his health issues, both physical and mental, disappeared. He was not the only one. Many of his patients that have received metal-on-plastic replacements also experienced neurologic problems that presented themselves like Alzheimer's and Parkinsons, and were not aware that their symptoms could be reversed until Dr. Tower's personal experience gave him the knowledge to recognise such symptoms of cobalt poisoning. It is scary to think how even our doctors fall for the dirty tricks of the medical device industry.
Dr. Tower’s hip during surgery to revise his MoM hip revealed metal sludge surrounding the joint and liquefaction of the hip capsule (containing critical ligaments that keep the hip in place)
Often it is assumed that all medical devices that go on the market undergo the Premarket Approval (PMA) process, or another equivalent for places outside the US, where devices go through rigorous and complete testing to ensure its safety for public use. Since medical device companies are constantly churning out new variations of devices that already exist and making changes to old products, the industry argues that it is too costly (money-wise) to be testing each small edit in humans. So thus the 510(k) process was instituted. Products deemed to be ‘substantially equivalent’ to another device that already exists on the market are cleared without needing to go through any clinical trials, thorough data collection and consultation with scientists like the PMA does. It was only meant as an exception but companies took profit and suddenly 95-98% of devices on the market were cleared by the 510(k). A bill was proposed by the Congress to seal this loophole in 2012 but was denied and it remains legal to put a new medical device on the market without testing it if it is similar enough to one that already exists, even the dangerous ones.
While metal-on-metal implants are no longer used in the US for total hip replacements we can only think of the 10 million who had already received chrome-cobalt implants, the millions more that have suffered at the cause of faulty, untested devices which cunningly made it to market by the 510(k) rule and the people the rule continues to harm.
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Center for Devices and Radiological Health. “Concerns about Metal-on-Metal Hip Implants.” U.S. Food and Drug Administration, FDA, www.fda.gov/medical-devices/metal-metal-hip-implants/concerns-about-metal-metal-hip-implants.
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