Damaged Caused by Metal-on-Metal Hip Implants is More Extensive Then First Thought

As feared more and more patients with metal-on-metal hips, like Johnson & Johnson’s ASR and Pinnacle hip systems, are undergoing revision and replacement surgery. Orthopedic surgeons are seeing more extensive damage than pre-operative tests indicated. The New York Times reported that it is likely that the damage might be permanent.

The metal debris shed by all metal hips, like the ASR, Pinnacle and Ultamet hip, release metal particles into the body. The body’s response to metallic particles is aggressive. Scavenger cells are sent to digest the metal particles converting them into metallic ions, like chromium and cobalt. It is believed that these active metallic ions pose a significant threat to the body resulting in early device failure, tissue damage and muscle damage. In some cases the tissue is so damaged it becomes necrotic.

The damage caused by metal-on-metal hip implants is not easily detected. Some patients with high blood levels of metallic debris, like chromium and cobalt, experience symptoms like pain and loosening of the device while others do not. The damage to the tissue and muscles can occur even in patients with low or normal blood levels of metallic debris and who have no symptoms indicating failure of the hip implant.

Unfortunately, orthopedic surgeons are not able to provide patients who have a metal-on-metal hip implant with a clear prognosis. Dr. Young-Min Kwon, was quoted in the New York Times as describing the metal-on-metal hip implant failures as a “complex phenomenon.”