I've heard that having a hip replacement with a metal implant can increase my chances for cancer. Is that really true?

Hip replacements are made from a variety of materials such as ceramic, polyethylene (plastic) and metals such as titanium, high-carbide cobalt, and chrome. A popular implant has a metal-on-metal (MOM) design. It gives the hip smooth action. But with repeated motions, flecks of metal ions are released into the joint and into the blood stream.

Metal ion release may be a factor in implant loosening. Some patients are hypersensitive to these particles and develop hip pain as a result. And there's been some question about the possibility of an immune system response to the foreign debris being linked with cancer.

Particles of both cobalt and chromium have been found in urine, blood, and organs of the immune system (e.g., spleen, lymph nodes) and in red blood cells and the liver. There are no reported cases of cancer linked with debris from hip replacements. For now, it's just a theoretical possibility. This will bear warching in future studies.