Stryker’s recent recall of two metal hip implant components, the  Rejuvenate Modular and ABG II modular-neck hip stems, may have dealt a serious blow to one of the key arguments medical device manufacturers have made to defend their metal-on-metal hip replacements.  Facing thousands of lawsuits, the makers of all-metal hip implants have asserted that such devices are too different to be classed together, and should be evaluated as a group.  But according to a report from Law360.com, the fact that the two hip implant components recalled by Stryker have been linked to the same types of metallosis injuries associated with metal-on-metal hip replacements severely undermines that argument.

Metal-on-metal hip replacements are devices in which both the ball and socket are made of metal alloy.  In recent years, it has been discovered that metal debris shed from metal-on-metal hip implants can leach into surrounding tissue, and sometimes the bloodstream.  This phenomenon has been linked to serious complications in patients with the devices that cause the implants to fail prematurely, including adverse local tissue reactions and the development of pseudotumors.

Stryker recalled the Rejuvenate and AGB modular-neck hip stems and terminated global distribution of the products on July 6, 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. Both of the Stryker hip implant components are two-part modular-neck systems that consist of a metal neck inside a metal stem. In May, Stryker released a report that found that such implant systems may suffer from the same types of adverse local tissue reactions that have been seen in patients who have received metal-on-metal devices  The report advised that patients fitted with modular-neck hip implant systems who experience unexplained, persistent pain  undergo medical evaluations similar to what has been recommended for all-metal hip implant recipients, including “serum metal ion levels, metal hypersensitivity testing and radiographic analysis including plain radiographs and preferably a metalartifact reducing MRI.”

According to Law360.com, Johnson & Johnson and its DePuy Orthopaedics unit, Smith & Nephew PLC, Wright Medical Technology Inc, and Biomet Inc. have all been named in lawsuits alleging their metal-on-metal hip replacement devices caused patients to suffer debilitating injuries.  Last month, during a meeting of medical experts convened by the U.S. Food & Drug Administration (FDA) to examine the safety of all-metal hip implants, manufacturers urged the panel to consider the devices on a case-by-case basis, and not as a class, when evaluating their safety.  It’s expected they’ll use that same argument in court as part of their defense strategy in metal-on-metal hip implant lawsuits, Law360.com said.

Some attorneys interviewed by Law360.com said they thought Stryker’s recall would hurt that argument, and boost plaintiffs’ claims that any type of metal-on-metal junction can cause serious injuries.  “When you put a metal-on-metal component in someone’s body and subject it to the type of friction and stress these implants are, you’re going to see problems with metallosis,” one plaintiffs attorney told Law360.com.