Cobaltism Dangers to Patients With Metal On Metal Hip Implants

Depuy Orthopaedics Inc., a division of Johnson & Johnson recalled its metal on metal (MoM) Articular Surface Replacement (ASR) in August of this year due to a greater than 12 percent failure rate during the first five years of implantation. DePuy estimates that 93,000 ASR hips have been implanted and it recommends that ASR implantees be monitored for Cobalt if they have hip pain, or if the femoral head is less than 50 mm in diameter. Cobalt poisoning is known to result in cardiomyopathy (Cardiomyopathy is a weakening of the heart muscle or a change in heart muscle structure. It is often associated with inadequate heart pumping or other heart function problems); goiter, hypothyroidism, polycythemia, EEG changes, peripheral neuropathies and optic neuropathies. Cobalt poisoned patients may present with breathlessness, irritability, headaches, weight loss, dysesthasias (distortion of the sense of touch), tremors seizures and weakness. Most metal on metal bearings produce microscopic metallosis. Gross metallosis can produce extreme levels of cobalt and chomium in blood and tissues. Steens et als. Chronic cobalt poisoning in endoprosthetic replacement. Orthopade. Aug 2006;35:860-864. Reports have recommended that patients with Cobalt levels greater than 7 warrant further evaluation and consideration of revision surgery if they have pain or evidence of periprosthetic fluid collections or masses.
Cobalt is neurotoxic and epileptogenic. There is no reported study of metal on metal implantees having their cobalt levels monitored over time and also no monitoring for neurogenic of cardiac impairments. Studies show that cobaltism may demonstrate through symptoms including tinitius (ear ringing); deafness; vertigo; visual changes; rashes; hypothyroidism; tremor and peripheral neuropathy; mood changes; dimentia; heart failure and more.ΠJeffrey Newman is an attorney and writer in Boston. His blog is FUTUREVIGIL.COM. He represents individuals with defective hip implants and whistleblowers and his email address is