On July 20, Stryker Orthopaedics announced the recall of the Stryker Rejuvenate hip replacement system and the ABG II modular neck hip stem. Before the recall, it is estimated that 20,000 of these Stryker units were sold in the United States alone. Over 60 adverse reactions were reported to the FDA in the wake of the Stryker implantations. One major cause for concern is that both systems were intended to provide an alternative to metal-on-metal replacements that can abrade or cause corrosion, metallosis and numerous other health risks to implanted patients. The Rejuvenate hip replacement was specifically marketed as an implant for younger patients who would need a greater range of motion. Both systems do contain metal in components which touch and can abrade or corrode. Numerous patients have required removal or revision surgery shortly after implantation.