A report published by Stryker in May, just weeks before it recalled its Rejuvenate Modular and ABG II modular-neck hip stems, found that such devices have the potential to cause problems similar to what has been seen among some patients who have received metal-on-metal hip implants. Like those controversial devices, the recalled Stryker hip replacement components can rub against one another, causing wear that allows metallic debris to shed into surrounding tissues and potentially into the bloodstream.
The recalled Stryker hip implant components are two-part modular-neck systems that consist of a metal neck inside a metal stem. According to the Stryker report entitled “Evaluation of painful total hip Replacements with Modular Metal Taper Junctions,” patients who have received such implants may suffer from the same types of adverse local tissue reactions that have been seen in patients who have received implants where the ball and socket were entirely made of metal (i.e. metal-on-metal hip implant devices). Such reactions often result in “premature failure due to osteolysis, aseptic loosening and in some instances a devastating pseudotumor formation,” the report said.
The Stryker report advises that patients fitted with modular-neck hip implant systems who experience unexplained, persistent pain undergo medical evaluations that “should likely include serum metal ion levels, metal hypersensitivity testing and radiographic analysis including plain radiographs and preferably a metalartifact reducing MRI.”
Stryker recalled the Rejuvenate and AGB modular-neck hip stems and terminated global distribution of the products after continued post-market surveillance indicated the devices may be prone to “fretting and/or corrosion at or about the modular-neck junction,” which may lead to pain, swelling and adverse reactions in surrounding tissue. According to Stryker, patients with the recalled hip implant components should schedule an office visit with their surgeon if they are experiencing symptoms of a malfunctioning hip implant. Those without symptoms should continue to follow the post-operative plan their surgeon has outlined. Affected patients may present with symptoms of pain and/or swelling at the local joint site not attributable to other conditions, such as aseptic loosening and periprosthetic sepsis.
The U.S. Food & Drug Administration (FDA) has received over 60 adverse event reports related to the recalled Stryker hip implant devices. According to one report submitted by a single doctor in March 2012, six of his patients fitted with the Rejuvenate device had developed metal sensitivity not long after being implanted with the Rejuvenate device. Such reports prompted Stryker to issue a letter to surgeons in April 2012 warning about the risk of metalloids that could be associated with the implant.