The typical hip implant system is a one-piece neck and stem construction known as a monoblock. Both Stryker’s Rejuvenate and ABG II products were designed as a system or series of different stems and necks that could be mounted together to more closely mimic a patient’s particular anatomy and physiology.
The Stryker Rejuvenate modular-neck stem was approved by the FDA in June of 2008. The hip was engineered to more closely model the biomechanics and anatomy of the human hip and provide enhanced stability. It was also designed to make implantation easier for the physician due to its “flexible system.”
The Stryker ABG II modular-neck stem device was approved in November of 2009. Both new products were marketed toward younger patients and advertised as “high performance.” They were supposed to resist metal fatigue, corrosion and theoretically last longer.
Unfortunately, since their neck components are made of chromium and cobalt, and the stems are coated with titanium, they can shed metallic debris into the body when they wear against each other, leading to further complications.
In 2012 Stryker Corporation issued a voluntary recall for both the Rejuvenate Modular and ABG II Modular-Neck Hip Stems. The company stopped all global sales and production of these products and is facing an ever-increasing number of lawsuits filed by patients who received the recalled hips.
In February 2012, three months prior to the hip recall, Stryker issued an “Urgent Field Safety Notice” to implant surgeons and hospital risk managers indicating the potential health hazards associated with the two products. The side effects stated include corrosion, fretting (a condition where minute shards of metallic components leach into a patient’s tissues, bones and/or bloodstream), and an increased rate of Adverse Local Tissue Reaction (ALTR) resulting in inflammation in and around the implant.
In April the same year, a second “Urgent Field Safety Notice” was issued by the company to surgeons and hospitals. It stated “excessive metal debris and/or ion generation” caused by “fretting and/or corrosion at or about the modular neck junction” that “may lead to increased metal ion generation in the surrounding joint space.”