USA Today—February 8, 2012
Faulty hip joints implanted in tens of thousands of Americans pose adverse health effects in some patients even after removal, according to new research.
Doctors have known for several years that some hip devices, in which both the ball and cup are made of metal, were failing at faster rates than other hip implants. Research to be presented Wednesday, at the annual meeting of the American Academy of Orthopaedic Surgeons in San Francisco, shows that debilitating problems from all-metal implants can persist for years.
Bostrom said metal-on-metal hip implants were sometimes used in younger patients who wanted to remain active in sports.
Damage to the body occurs, Bostrom said, when the implant pieces move against each other and metal debris breaks off, lodging in nearby soft tissue and bone and entering the blood.
In a 12-month period from 2005 to 2006, nearly 40,000 metal-on-metal hip replacements were performed in the USA, accounting for 32% of all hip replacements during that time, the American Society of Hip and Knee Surgeons said.
About 500,000 people are estimated have them. About 285,000 hip replacements are performed a year, the Agency for Healthcare Research and Quality said.
Many implants now are made of other components: metal and plastic, metal and ceramic, and all ceramic. Metal-on-metal implants designed to last 15 years were sometimes failing within several years.
Signs of failure include pain, swelling or onset of a limp.
Among other findings:
ĽOrthopedic surgeon Douglas Padgett, of Hospital for Special Surgery, said a study in which he was involved found 98% of the cups and 93% of the balls showed "moderate to severe scratching" in 46 retrieved metal-on-metal implants.