The annual meeting of the 2013 American Academy of Orthopaedic Surgeons (AAOS) in Chicago has just concluded and doctors delivered a mixed report on metal-on-metal hip replacements.
In a study presented from New York State’s Hospital for Special Surgery (HSS), researchers found unexplained pain in metal-on-metal (MoM) hip implant patients is more likely due to tissue damage surrounding the prosthesis rather than wear of the implant.
HSS is ranked nationally No. 1 in orthopedics by U.S. News & World Report and researchers wanted to know what caused the increasing number of unexplained pain complaints that eventually lead to hip revision. Among the 9,000 hip implant procedures done by HSS annually, 10% are revisions.
Researchers compared 50 patients who had unexplained pain to a control group of 48 patients who came to HSS with infection, fracture misalignment or loosening of the hip. They measured adverse tissue reaction to metal ions and conducted a wear analysis on removed implants.
Among the group with unexplained pain, 60% had moderate to high rate of tissue reaction and 12% had a buildup of metal ions in soft tissues. The age, sex, body mass, size and length of the implant did not seem to explain pain and patients in both groups had similar wear on the implants. Some patients had a lot of tissue damage, but that was not related to wear, suggesting other factors are causing the damage.
When metal hips were introduced, the industry thought MoM hips were a positive innovation in their ability to remain well-lubricated which minimizes wear, but the thousands of lawsuits filed by injured patients tell another story.
Metal-on-metal hip implants have unique risks. In a MoM hip, the ball and socket is made of metal, usually chromium and cobalt. The metal components can come in contact during walking or running which can release metal particles around the implant, the tissue and surrounding muscles. The scientific community believes the metal ions causes damage that is irreversible and can lead to an early revision of the hip implant.
The suggestion is for doctors to closely follow hip implant patients with unexplained pain before there is significant tissue damage.
AAOS members also sang the praises of a total hip replacement (THR) concluding itincreases the life span and reduces the risk of heart failure, depression and diabetes among the 43,000 Medicare patients with osteoarthritis that were studied.
The study was undertaken to determine the cost-effectiveness of THR treatment seven years after implant but the findings reveal that hip recipients cost Medicare $6,000 more than non-THR patients.
Article Source: http://www.strykerimplantrecall.com/2013/04/04/study-metal-hip-pain-and-tissue-damage/