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Cobalt was widely used for hip and knee joint replacements due to strength and durability, but this led to cases of heavy metal poisoning. Toxicity can arise from cobalt and other metals if they accumulate in body tissues at high levels. After years of implant wear and tear, metal particles can build up around the joint and cause pain, inflammation and dark discoloration.
Teams at the University of Connecticut School of Medicine and Carnegie Mellon say they can protect people from this toxicity, called metallosis.
They say implant removal represents “the obvious solution.” However, invasive revision joint surgery brings risk with it. According to the team, traditional chelation therapy is another option. In this therapy, a drug binds the heavy metal and allows the body to excrete it. However, this has a difficult time penetrating joints and surrounding tissues.
Researchers found that injecting a material made of traditional chelator combined with a molecule naturally found in the fluid surrounding the joints makes an effective, less invasive therapy to clear out cobalt. They used a chelator called British anti-Lewisite (BAL). This treatment originally helped soldiers poisoned with arsenic-containing Lewisite during World War II.
The teams attached the BAL to hyaluronic acid and injected it into the hip joints of rats with cobalt metallosis. Within hours, they say the acid cleared a great deal of cobalt into the bloodstream and kidneys so the rats could excrete it.
“This unique approached developed by teams at The Cato T. Laurencin Institute and the department of chemistry at Carnegie Mellon University offer a possible breakthrough treatment for metal ion disease after joint replacement,” said Dr. Cato Laurencin, CEO of the Cato T. Laurencin Institute for Regenerative Engineering. “Now that we know it works in animals, our hope is to eventually bring this type of therapy to humans,” he says.
