The Rejuvenate and ABG II Hip Systems differ from other metal-on-metal devices because they do not have metal-on-metal ball (femoral head) and socket (acetabular cup) components. For this reason, some do not consider these devices metal-on-metal implants. In any case, the devices do have titanium hip stems that join with necks made of Cobalt and Chromium. Corrosion or fretting at this neck-stem junction can cause the same complications, i.e., metal toxicity, as devices that have metal ball and socket components.
According to an “Urgent Safety Alert” that Stryker issued April 6, 2012, metal debris from the devices can lead to bone dissolution known as osteolysis, pseudotumors, tissue death, metallosis, and pain. Investigators do not yet know the full array of consequences from exposure to metal debris from these devices. Stryker has advised patients who received one of these devices and who are experiencing pain to undergo MRIs, X-rays, and blood tests to check metal ion levels.
In some cases it may be necessary to have revision surgery to replace part of the neck-stem junction with a ceramic component.