A metal-on-metal device made of chromium and cobalt, the DePuy ASR Hip Implant System consists of a cup implanted into the hip with a ball joint that connects to the leg. The ASR implants were recalled last August by DePuy Orthopaedics, a division of Johnson & Johnson, after data from a registry in the United Kingdom indicated a failure rate of 12 percent within five years of implantation. Since that recall, at least 1,000 DePuy ASR hip implant lawsuits have been filed by victims of the device in federal and state courts around the country. Hundreds of such claims have been consolidated in a multidistrict litigation in U.S. District Court for the Northern District of Ohio.

The new Wisconsin lawsuits allege the DePuy ASR implant can come loose, cause infection and fracture surrounding bone. They also could increase levels of metal in blood and body tissues when the metal components of the implant wear, causing microscopic shards of cobalt and chromium to make their way into the bloodstream. As we’ve reported in the past, this can lead to even more serious long-term health problems including adding to tissue breakdown, bone loss, and even the formation of non-cancerous tumors, and even cobalt poisoning.

In recent years, concerns over problems with metal-on-metal hip replacements have been growing. Last month, the U.S. Food & Drug Administration (FDA) asked DePuy Orthopaedics and 20 other manufacturers of metal-on-metal hip implants to conduct safety studies aimed at determining if these devices are shedding dangerous amounts of metallic debris in patients. They have also been told to determine how often their metal-on-metal hip implants fail prematurely. According to an FDA official who spoke with The New York Times, the agency had determined that there were “significant enough medical concerns to warrant a broad review of metal-on-metal hips.”

According to a report published by The New York Times in March 2010, metal-on-metal hip implants have been used in about one-third of the approximately 250,000 hip replacements performed annually in this country. However, many of the nation’s leading orthopedic surgeons have reduced or stopped use of these devices because of concerns that they can cause severe tissue and bone damage.