Metallosis Linked to Metal-on-Metal Hip Implant may lead to Dementia-Like Symptoms

DePuy ASR hip recall 435x369 Metallosis Linked to Metal on Metal Hip Implant may lead to Dementia Like SymptomsRecently, a Texas jury awarded six plaintiffs with a $1 billion verdict against DePuy Orthopaedics, a subsidiary of Johnson & Johnson, over its metal-on-metal hip implant design that many patients claim has caused them pain, inflammation, bone erosion, tumors and tissue death. The company is facing a total of 8,900 lawsuits from people who say they have experienced adverse effects from the artificial hip.

The metal-on-metal hip implant is a design meant for younger patients, or patients who have a more active lifestyle. They were intended to be more sturdy and durable with a longer lifespan than traditional ceramic implants, but have been known to fail in as little as two years, while hip implants made from other materials can last 20 years or more.

The hips, such as the Pinnacle ASR by DePuy, are a metal ball and metal socket design made of a cobalt-chromium alloy. The parts rub together during normal use, shedding metal ions into the tissue and bloodstream. The corrosion has been linked to metallosis, a medical condition in which the patients’ blood is found to contain elevated metal levels. Many patients have experienced cobalt poisoning, which has been linked to symptoms such as a tremor, poor coordination, cognitive decline and depression as well as damaging effects on the heart, hearing and vision.

In one recent study, a patient referred to as “Mrs. Z” had her right hip replaced with an ASR metal-on-metal system at the age of 51. Seven years later, she was forced to have revision surgery, complaining of poor sleep while waking up early in the morning, low mood, poor appetite, and forgetfulness. According to her family, she began repeating herself. She expressed frustration at being unable to do everyday activities such as cleaning, and felt she was a burden to family and friends. Mrs. Z began withdrawing from social activities.

Normal cobalt/chromium levels in a person’s blood ranges around  0–20 nmol/l for cobalt and 0–100 nmol/l for chromium. Mrs. Z, however, had cobalt levels at 544 nmol/l and chromium levels at 326 nmol/l. During her mini mental state examination, Mrs. Z scored a 17, a score linked to her toxic cobalt levels. A score less than 25 is considered to be a possible dementia indication.

Source: BMC Psychiatry