Why Blood Testing is Crucial to Detect Metal Toxicity In Patients with Stryker Hip Implants

Metal hip implant recipients are likely very aware of the problems associated with the cobalt and chromium parts of the implant devices. The Stryker Rejuvenate and ABG II, both recalled in July, 2012, are not true metal-on-metal hip implants, but have found to have many of the same risks and dangers. The Rejuvenate and ABG II have a metal neck juncture as well as small metal trundles located on the neck piece. When the two models were recalled Stryker cited the risk of fretting, corrosion and early implant failure.

When the metal parts of the implant corrode, tiny metal particles can shear away from the implant, burrowing into surrounding hip tissues or entering the bloodstream. Metal toxicity can result from cobalt and chromium in the bloodstream and can have very serious consequences. Neurological, cardiovascular, gastrointestinal, renal and thyroid issues have all been found among those with high levels of cobalt and chromium as well as depression, anxiety, irritability, DNA disruption, vertigo, pseudotumor formation, vision and hearing loss and chronic headaches and pain.

There are several tests to measure the levels of cobalt and chromium in the bloodstream, including:

·         Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

·         High-Performance Liquid Chromatography

·         Field-Flow Fractionation (FFF)

·         Isotope/Metal Speciation

The ICP-MS test is faster, more precise and more sensitive than the older atomic absorption tests and is able to detect metal levels as low as one part per trillion. A blood sample from the patient is ionized with inductively coupled plasma. A mass spectrometer then separates the plasma in order to record the levels of metals in the bloodstream. The high-performance liquid chromatography test may be used to test for abnormal levels of cobalt and chromium among those with metal hip implants. Chromatography consists of a mass transfer process which relies on pumps to send the sample of blood through a silica-filled column. This effectively separates the blood components from one another after which a digital microprocessor provides the blood analysis.

FFF uses fluid suspension to separate the blood sample as it is pumped through a long narrow channel. The blood may be sent through an electrical, gravitational, magnetic, centrifugal or thermal-gradient membrane in order to achieve separation. The resulting fractogram identifies the various levels of metals in the bloodstream as well as other species according to physical and chemical properties. Isotope/metal speciation can be used to measure levels of hexavalent chromium in the body. Remember that trivalent chromium is necessary for the normal function of the human body however hexavalent chromium is extremely toxic to the human body, potentially leading to cancer.

The recalled Stryker Rejuvenate and ABG II both have been found to have the potential to send cobalt and chromium into the body, causing a wide variety of adverse health symptoms. Patients who have chronic pain in the hip joint or notice any inflammation in the area should see their physician as soon as possible to undergo blood tests, MRIs and x-rays. Should the hip fail, revision surgery—both riskier and more complex than the original surgery—will be necessary.