Recent reports show that metal-on-metal hip replacements fail at a much higher rate than their ceramic and plastic counterparts, requiring additional surgeries. Now, researchers are reporting another risk linked to the dangerous medical products – high levels of toxins that seep into patients' bloodstreams, causing serious health complications like muscle and bone damage, genetic changes, and even cancer.
According to the new report, published in the British Medical Journal, chromium and cobalt ions can destroy muscle and bone and spread to the lymph nodes, spleen, liver, and kidneys. Researchers said that a design change in the past decade intended to increase movement for the implant recipient causes the release of the toxins.
They also discovered a 2005 internal memo from DePuy Orthopaedics, a division of Johnson & Johnson, showing that the company knew about the possible toxicity of the implants in 2005. According to the memo, "…there has been concern for some time that wear debris may be carcinogenic... One study suggested a threefold risk of lymphoma and leukemia 10 years after joint replacement."
Despite the memo, investigators concluded that marketing of the metal-on-metal hips "continued unabated."
The UK's regulatory agency, the Medicines and Healthcare Products Regulatory Agency (MHRA), has updated its guidelines for patient management and monitoring for surgeons and doctors, saying that they should monitor the implants every year for a patient's lifetime.
The Food and Drug Administration (FDA) approved the implants' new design in 2005 through a grandfathered process because it was similar to older implants. The agency hasn't changed its recommendations, saying that hip replacement patients should adhere to normal follow up procedures.