Stryker Hip Implants: What Are The Medical Concerns?

Stryker Orthopedics has recalled its Rejuvenate and ABG II hip implant components because they are shedding metal particles that cause two different types of medical concerns. First, the particles contain toxic levels of cobalt and chromium that cause local tissue reactions. These reactions include pain at the implant site, which can limit the function of the implant. These tissue changes can cause fluid collections that resemble tumor tissue (pseudotumor), and local tissue death (necrosis). Another type of tissue change is referred to as aseptic, lymphocyte-dominated vasculitis-associated lesions (ALVAL). These tissue changes can also lead to painful and expensive hip dislocations. Osteolysis can sometimes be triggered, which is a type of bone loss. Such bone loss can occur as early as 12 months after implantation, and it is usually progressive. Osteolysis often does not cause symptoms. However, it can lead to implant loosening and bone fractures that create serious medical problems.

The second concern is that these toxic metal particles infiltrate the blood stream and cerebrospinal fluid, thereby traveling throughout the body to seed into distant tissues and organs. Cobalt exposure is known to cause neurologic (central and peripheral), endocrine, and cardiac manifestations. Combinations of tinnitus, vertigo, deafness, visual impairment, electroencephalographic changes, weakness, muscle atrophy, paresthesias, hypothyroidism, and heart failure have been noted. Patients also frequently describe mood changes, depression, memory changes, inability to concentrate, weight loss, headaches, irritability, fatigue and muscle atrophy.

Because of these medical concerns, revision surgery to remove these implant components is usually recommended.