Metallosis is the putative medical condition involving deposition and build-up of metal debris in the soft tissues of the body.Metallosis has been known to occur when metallic components in medical implants, specifically joint replacements, abrade against one another. Metallosis has also been observed in some patients either sensitive to the implant or for unknown reasons even in the absence of malpositioned prosthesis. Though rare, metallosis has been observed at an estimated incidence of 5% of metal joint implant patients over the last 40 years. Women may be at slightly higher risk than men. If metallosis occurs, it may involve the hip and knee joints, the shoulder,  wrist, elbow joints, or spine. In the spine, the wear debris and resulting inflammatory reaction may result in a mass often referred to as a "metalloma" in medical literature, which may lead to neurological impairment over time. A similar condition has been also described when titanium dental implant degradation occurs leading to inflammatory titanium particle-mediated Peri-implantitis. Titanium particles in the peri-implant tissues do not occur via functional abrasion but are thought to result from damaging hygiene procedures or due to complex electrochemical interactions caused by oral bacteria.The abrasion of metal components may cause metal ions to be solubilized. The hypothesis that the immune system identifies the metal ions as foreign bodies and inflames the area around the debris may be incorrect because of the small size of metal ions may prevent them from becoming haptens. Poisoning from metallosis is rare, but cobaltism is an established health concern.
DePuy hip replacement recall

In August 2010, DePuy recalled its hip replacement systems ASR XL Acetabular Hip Replacement System and ASR Hip Resurfacing System due to failure rates and side effects including metallosis. The recalls triggered a large number of lawsuits against DePuy and its parent company Johnson & Johnson upon claims that the companies knew about the dangers of the implants before they went on the market in the United States. == References ==