Irish health regulators have ordered a major review of all patients with artificial hips made with all metal parts. The order follows an investigation last year by the United Kingdom’s medical devices regulatory agency during which it was recommended that patients with metal-on-metal hip replacement systems be checked on a regular basis for indications of device failure and a type of metal poisoning caused when the device begins to corrode.
Traditional hip implants are made with ceramic or plastic parts. A decade ago manufacturers introduced devices made with all metal parts expecting they would be more durable. However, the devices began failing at a higher than expected rate after five years or less.
The problem with the metal-on-metal devices was the material. As the metal parts rubbed together, bits of metal debris would fall into the joint space causing tissue damage and inflammation, and pain for the patient. The tiny metal pieces – bits of chromium and cobalt – were also leeching into the bloodstream causing a type of blood poisoning known as metallosis.
Many patients diagnosed with metallosis have experienced symptoms including headaches and fatigue. The long term effects have yet to be realized. Some researchers say heavy metals in the blood can damage DNA, which can lead to serious health complications, including cancer.
Metal-on-metal hip implants have been made by several medical device manufacturers, however many are being phased out due to the safety concerns.
It is recommended that patients who have metal-on-metal hip replacement systems be checked annually by their doctors to ensure their implant is working properly, and have a blood test to check for any signs of metal poisoning.