Corroding debris from failing metal-on-metal artificial hips release Cobalt 2+ ions in surrounding tissue, which cause inflammation and may also do damage to DNA which could result in medical complications including cancer, according to researchers from Imperial College London and Ohio State University.
Metal-on-metal hip replacement systems were introduced in the early 2000s as a more durable alternative to traditional ceramic or plastic hip implants. But the devices began failing at higher than expected rates after just five years or less.
What surgeons found is that the failures were triggered by inflammation in the tissue surrounding the implant. This inflammation was linked to bits of metal debris that can break loose when the metal parts of the implant rub together. Symptoms from this inflammation include chronic pain and loss of mobility.
Most disturbing is that this metal debris – bits of chromium and cobalt – is showing up in patients’ blood. Some patients reported fatigue, headaches and other problems, but no one could say for sure what the long-term risks could be.
Now, researchers have used a new approach that combines high-resolution X-ray and electron microscopy to test tissue samples from affected patients. They discovered that residual chromium is oxidized and Co2+ ions are released as the nanoparticles corrode in the tissue. This causes the inflammation.
Previous studies have shown that Co2+ ions are genotoxic, which means they could potentially damage DNA, which would cause long-term medical complications including cancer.
“Even though a huge number of patients have benefited from replacement surgery, we still don’t fully understand the long-term impacts that implantable materials have on our bodies,” writes Dr. Mary Ryan, co-author of the paper that appears this month in the journal Chemical Communications. “Our work is one of the first to study these nanoparticles and the effects that they have on damaged cells and tissue. This has enabled us to understand in much more detail the side effects that these materials may have in patients.”
Image courtesy Zephyris at English language Wikipedia
Source: Medical Xpress