Patients who have undergone metal hip replacement surgery may be at risk for metal poisoning, or metallosis.

Metallosis, a type of metal poisoning, occurs when metal ions are shed into the patient’s bloodstream. The metal ions may shed from metal-on-metal hip implants where the pieces making up the ball and socket joint of the metal hip implant are both made of metal. The pieces are often made of a cobalt and chromium alloy, which emit particles when the implant parts interact.

The cobalt and chromium ions immediately attack the surrounding tissues, often near the joint where where metal ions build up. The build up spurs the body to react. Lymph nodes try to absorb the metal ions to transport them to the kidneys where they can be expelled through urination, but the large volume of metal ions is often too much.

Metallosis Hip Implant Complications

While patients may naturally be exposed to high levels of metal ions through their food or environment, metal-on-metal implants can introduce a high volume of metal to the body quickly. Metallosis can lead to a higher risk of cancer, severe pain and swelling, tissue and bone death, and device failure.

Metallosis is normally diagnosed through blood tests, after metal hip implant patients start complaining of pain and limited movement. Affected patients will have elevated metal ion levels in urine and blood samples, indicating that the patient needs to be treated.

Treatment options for severe metallosis often include revision surgery or chelation therapy to remove the excess metal ions.

The FDA recommends that metal hip implant patients undergo regular blood tests and other medical testing to watch for early signs of post-implant complications.

Metal hip implants became popular in the United States by offering features that their plastic and ceramic counterparts could not. These models could be custom fit to patients, and were advertised to last longer and better handle more intense movements like running.

Unfortunately, the devices came with a fairly significant drawback. Metallosis was first reported as a potential hip implant complication in the 1970s, when patients reported suffering pain and joint instability within five years of the hip implant surgery.

Today, numerous metal hip implant patients have taken legal action against the manufacturing companies for failing to warn of side effects such as metallosis.