Heavy Metal Toxicity and Metal Hip Implants – The silent disease

Over the past several years, the orthopedic device industry has come under heavy criticism from both physicians and regulatory authorities over the manufacture of hip implants that employ a design that results in metal parts rubbing on metal parts. The lingo that has developed refers to such devices as “Metal on Metal” or (MoM). Research has shown that when these devices are implanted in the human body, if they don’t fit just right or if the metal deforms in any way, metal debris from the device is created or cast-off into the human body. These devices were manufactured by Zimmer, DePuy, Wright Medical, and Stryker. At least one of these devices, the DePuy ASR, has been pulled from the market.

As a result, our FDA has ordered every company that makes these devices to redouble its post marketing surveillance of adverse event reports. Since this is a relatively new problem for the orthopedic community, doctors, scientists and the FDA are in the dark as to the exact nature of the consequences heavy metal toxicity causes to patients. Debate has arisen over whether all symptomatic patients who received metal on metal devices should be tested for metal levels. Even if patients are tested, there is a question as to exactly what should be tested. Should it be blood levels or synovial fluid? Evidence exists that concentrations of heavy metal ions are significantly higher in the area immediately surrounding the hip implant itself. Even our regulatory authorities and scientific community are at odds over exactly what levels of heavy metal ions are “safe.”

More recently, even hip implants that do not have metal balls and sockets have been linked to heavy metal debris complications and failures. These devices involve multiple parts that are assembled by the surgeon during surgery. Typically referred to as “modular hip systems” these devices don’t have metal balls and sockets but, they do have metal parts that come into contact with one another. Research has shown that heavy metal debris may be caused by the abnormal rubbing together of these parts. Scientists call this “fretting.” While the designs are dissimilar the mechanism of failure is the same. Metal rubbing on metal causes debris to collect inside a patient’s body.

Many problems have been associated with metal particles circulating around hip implants and in the bloodstream. Soft tissues may rot or die, pseudo tumors can form, bone may not grow normally and various neurological and cardiac problems have been linked to high metal ion counts. What is most concerning is that patients in whom these devices are implanted often experience severe pain and restriction of motion. They report these symptoms to their surgeon. The surgeon does a complete work up to rule out infection, malposition and device loosening only to tell the patient there is no explanation for their symptoms.

Yesterday I heard from yet another new client that he has suffered since having a Stryker Rejuvenate modular hip implant placed two years ago. Six months prior to having this device placed he had his opposite hip replaced with a different device. He was 39 years old so, when it came time to do his other hip, his surgeon convinced him that due to his age, the Stryker Rejuvenate hip would be better the second time around. Shortly after the hip was placed, he began experiencing groin pain. Over time the pain became worse and he began losing range of motion. His doctor performed a complete work up and ruled out all possible explanations for the patient’s symptoms. The client did some snooping around on the internet and found that his device had been recalled in Canada and that it had been linked to metallosis. So, he approached his physician and asked to be tested for heavy metal levels. The doctor’s response, “There’s no need for that.” Recently, the doctor told the client to quit coming in to see him as there was nothing left for him to do short of repeat surgery and there was no indication for that.

The client is at wit’s end. He is unable to return to his job in construction. His opposite hip has been perfect since it was implanted.

This story is consistent with many others we have heard over the past two years. Patients with painful, symptomatic hip implants submit to painstaking diagnostic testing only to be told there is nothing wrong with them. Their doctors are either reluctant or unwilling to test for heavy metals. So, they suffer along until their situation gets so bad, a sympathetic doctor takes them back to surgery only to find pseudotumor formation and black, necrotic tissue surrounding the implant. In the end, there was a perfectly good explanation for their symptoms. It is very frustrating for these patients.