Metal on Metal Hip Implants
Up until about a decade ago most hip replacement products were made of plastic and ceramic, with most devices using either ceramic on plastic or ceramic on ceramic. In an effort to create a more flexible device which was more attractive to a younger, more active group of patients the leading hip replacement manufacturers began producing metal-on-metal (MOM) devices, which were first approved for use in the United States by the FDA in 1999.
While these products generally offer both flexibility and reduced wear, the by-products of that wear, microscopic metal ions, have been shown to create a host of side effects, raising concerns over their long term viability.
Metal-on-Metal Hip Products
The list of medical device manufacturers that sell metal-on-metal hip devices include:
- DePuy Othopaedics
- Stryker Orthopaedics
- Zimmer Holdings
- Smith & Nephew
- Biomet Inc.
- Wright Medical Technology
DePuy, which is owned by Johnson and Johnson, began manufacturing MOM hip devices over a decade ago, including the Pinnacle, ASR XL Acetabular System and the ASR Resurfacing System. By 2010 both of the ASR products were recalled by DePuy after they were confronted with high failure rates with in a short period of time after they were introduced. Estimates of the number of lawsuits that have been filed or that eventually will be filed over these products exceed 10,000.
Stryker has two MOM hip devices, the Rejuvenate and the ABG II, both of which were recalled in July of 2012. Among other alleged complications regarding these products are device loosening and metallosis caused by the release of microscopic metal ions from the friction between the metal components. Lawsuits over these products have also been filed and are expected to run into the thousands.
Zimmer Holdings manufactures a metal hip socket, called the Durom Acetabular Component also called the Durom Cup, which was briefly recalled in 2008 to revise the instructions to doctors on how to use the product, then returned to the market.
Smith & Nephew manufactured a metal liner for its R3 Acetabular Device. This product was marketed to an estimated 4,000 citizens in the United States before the company recalled the product in June of 2012.
Biomet manufactures a number of hip devices containing metal, including their MOM implant known as the M2a.
Wright Medical has two MOM products on the market, including the Conserve Plus Total Hip Resurfacing System and the Profemur Z Hip Stem. It is alleged that both these products fail at rates similar to other MOM devices.
Metal-On-Metal Patient Alerts
Given the significant complications associated with metal-on-metal implants anyone who has received an artificial hip should check with their doctor as soon as possible to determine if they received a product containing metal components. If the patient has an implant with metal components, they should immediately discuss with their doctor the advisability of testing for excess levels of metal in their blood stream.
Even if a patient is currently experiencing no symptoms of product breakdown most experts agree that hip devices that cause elevated levels of metal ions in the body should be removed as soon as possible.