What Levels of Cobalt are Unacceptable?
The Stryker recalled hip implants—the Rejuvenate and the ABGII—while having a smaller surface of metal components which can suffer corrosion and lead to metal ions being released in the body, can nonetheless come with serious health risks. The metal ball and acetabular cup in other metal hip implants rub against one another creating tiny metal particles which can lodge in surrounding tissue or enter the bloodstream. These particles are a combination of cobalt and chromium and may lead to tissue damage, bone loss, chronic pain, failure of the implant and metal toxicity. Because the Stryker Rejuvenate uses a ceramic ball, it was originally believed there would not be the potential risks associated with a true metal-on-metal hip implant.
Unfortunately, the Stryker recalled models implemented a metal neck juncture as well as small metal trunnions one either end of the neck portion. Fretting and corrosion were found to be just as likely in the Stryker hip implants as in other all-metal hip implants, therefore cobalt levels are a serious concern. Those patients with a metal-on-metal hip implant may well wonder “What is a high level of cobalt in the blood from a hip?” This question can be somewhat difficult to answer as each person’s body will respond differently to cobalt in the hip tissues and in the bloodstream. Some patients who tested quite high for levels of cobalt have not yet begun to feel sick while others who have relatively low levels of cobalt in their bloodstream may have already experienced one or more of the many symptoms of metal toxicity such as:
· Gastrointestinal, neurological, renal, cardiovascular and thyroid issues
· Loss of hearing or vision
· Vertigo
· Memory loss
· Depression, anxiety, irritability
· DNA disruption
· The development of pseudo-tumors
Are There any Safe Levels of Cobalt?
Due to the smaller metal surface area of the Stryker Rejuvenate and ABGII, blood tests for the metal cobalt may not show the extremely high levels seen in those with all-metal implants, however serious side effects—some of which can be long-term and debilitating—can be seen. In the end, there is really no “safe” level of cobalt in the human body other than the microscopic amounts which occur normally. A normal, healthy person may test approximately 0.5 parts per billion of cobalt in the body; while some doctors believe any amount over two parts per billion is a health risk, most scientists maintain that any level up to five parts per billion is relatively safe.
What Do the Numbers Mean in a Stryker Recalled Hip Implant?
Further, while a DePuy ASR or Pinnacle patient may test cobalt levels as high as in the twenties due to the large metal surface area, smaller numbers are just as concerning coming from a Rejuvenate or ABGII patient as the cobalt is coming from a joint which is not supposed to wear at all. This means a patient with cobalt levels as high as three could have a Stryker hip implant which has experienced serious wear issues. Stryker hip implant recipients should have regular cobalt testing done, particularly if the patient experiences any unusual or worsening pain in the hip or groin area. Consult your doctor in order to determine what is a high level of cobalt in the blood from a hip in your specific case.