Many studies show severe complications as a result of metal-on-metal hip replacement, but many patients continue to sign up for this surgery. A recent study shows high rates of psuedotumor formation in patients who have received metal-on-metal hip-replacement devices.

The concept of a minimally invasive hip-replacement surgery began with much fanfare about 10 years ago. It wasn’t long before the Internet was buzzing with discussions about how this surgery could reduce downtime and speed recovery—at least until it all went horribly wrong. In order to allow the smaller hip-replacement components to survive the same forces, the parts were manufactured so that metal on one side would touch metal on the other. The consequence of metal rubbing against metal millions of times is the production of metal shavings. When this occurs in the human body as a result of hip-replacement surgery, these shavings eventually fill whatever is left of a patient’s hip joint, causing a high number of metal ions and black soot-like particles in the patient’s blood serum. The metal particles cause a strange tissue reaction, sometimes creating a psuedotumor, something that looks like a tumor. These psuedotumors can press on the nerves, arteries, and veins near the hip joint, causing new problems.

Just how common are these pseudotumors? The study published in the March 2015 issue of Archives of Orthopaedic and Trauma Surgery sought to find out. Over a three-year period, the authors looked at 706 hips in 626 patients who had received larger metal-on-metal hip devices. They found 228 pseudotumors one inch or larger. That’s a startling one-third of the patients. Pain after the hip replacement was the strongest predictor of a golf-ball-sized or bigger mass due to the metal-on-metal hip.

“New Hip-Replacement Device Causes Tumors in a Third of Patients” first appeared as a post on the Regenexx blog.