Metal-on-Metal Hip Implant Study Sees Possibility of Long-Term Damage from Toxic Nano-ParticlesJul 5, 2012 | Parker Waichman LLP
Another study is pointing to possible long-term health consequences from metal-on-metal hip implants. According to the study, published online in the journal Chemical Communications, failing metal-on-metal hip replacements can shed genotoxic nano-particles into surrounding tissue, which over time could damage the DNA of cells.
"We were able to meet patients who had these failing implants and we could see first-hand the chronic inflammation, pain and loss of mobility they experienced,” said Dr Mary Ryan, co-author of the paper from the Department of Materials at Imperial College. "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.”
The research team used high-resolution X-ray and electron microscopy to determine the cause of inflammation in tissue samples obtained from victims of failing metal-on-metal hip implants. They found that the inflammation was the result of the oxidation of residual chromium being oxidized and the Cobalt 2+ions, both of which result when nano-particles corrodes in the tissue. The nano-particles shed from the hip implants had accumulated in white blood cells, where a corrosion process causes the cobalt to dissolve rapidly and be released into the surrounding tissue and blood stream. The less soluble chromium remains in the tissue as a solid residue.
The study authors expressed concerns that the genotoxic nano-particles could be doing long-term damage. They pointed out that studies have shown that Cobalt 2+ions are genotoxic, meaning they could potentially damage DNA
"There is a double edged sword to these findings because on the one hand, we’ve found a root cause of inflammation, which may lead to better intervention therapies for patients," Dr Alexandra Porter, co-author also from the Department of Materials at Imperial. "On the other, although we still need to do more work to understand the full impact; our results suggest that these nano-particles may have a long-term genotoxic impact on patients.”