Sunday, July 8, 2012

Yet another study seeing potential long term toxic effects of the Metal on metal hip

http://pubs.rsc.org/en/content/articlelanding/2012/cc/c2cc33016d

Chemical Speciation of Nanoparticles Surrounding Metal-on-Metal Hips
Angela Goode , James Perkins , Anne Sandison , Chithra Karunakaran , Huikai Cheng , David Wall , John Skinner , Alister Hart , Alexandra E Porter , David W McComb and Mary P Ryan                                           
 
 
Chem. Commun., 2012, Accepted Manuscript
 
 
The premature failure of Co-Cr based metal–on-metal hip implants has been linked to the presence of nanoparticulate debris released into the host tissue during wear of the implanted device. Here we report the first direct STXM-EELS correlation in human tissue: the chemical nature of the nanoparticle debris has been determined using a multiscale correlative approach employing optical, X-ray and electron micro-spectroscopy. The analysis was performed on tissue removed from patients during implant revision surgery: nanoscale debris in periprosthetic tissue was found in two distinct chemical states inside the macrophage cells. The majority of debris consisted of diffuse deposits composed of chromium solely in the 3+ valence state, with trace amounts of oxidised cobalt. A second minority phase containing a core of metallic chromium and cobalt was also observed. These data indicate that metallic particles reach the surrounding tissue (i.e. are not fully reacted within the synovial fluid) and that significant dissolution is occurring in the tissue.


                                   
 
 
 
 
 
 
 

Long-Term Health Risks Associated with Genotoxic Nanoparticles Released by Failing Metal-on-Metal Hip Implants

Published on July 7, 2012 at 4:42 AM
By Cameron Chai (Parker Waichman excerpts)

A recently published study on failing metal-to-metal hip implant devices reveals that the genotoxic nanoparticles released could cause severe damage to cell DNA.



The study carried out by a team of researchers from Ohio State University and Imperial College, London and published in the online journal of Chemical Communications identified the genotoxic nanoparticles to be not only responsible for inflammation commonly found in hip implant patients but also as a potential source of long-term health risks.

The research team employed high resolution electron and x-ray microscopy to study tissue samples from patients of failing metal-to-metal hip implants for identifying the causes of chronic inflammation suffered by them. They discovered that the inflammation was a result of oxidation of residual chromium shed when the metal implants rub against each other and the release of Cobalt 2+ ions as a result of nanoparticle corrosion in the tissue. Previous studies have established the genotoxicity of Cobalt 2+ ions.


[I have been publishing extensively about the issues surrounding oxidative stress for months now including but not limited to the implications of my own unexpected return of my renal cell carcinoma and these metal on metal hips.  You can see these  publications here:

 
 
 
 
If you type in oxidative stress into the search tool on the blog there are probably 20 posts on this issue.  Glad to see that researchers are beginning to study these potential links.
 
Connie]
 
http://pubs.rsc.org/en/content/articlelanding/2012/cc/c2cc33016d

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