It's not based on damage to the knees' cushioning elements, study suggests
FRIDAY, Nov. 30 (HealthDay News) -- Damage to the menisci -- the knees' "shock absorbers" -- is sometimes associated with knee osteoarthritis, but it does not directly provoke pain, aching and stiffness, a U.S. study finds.
"Any association between meniscal damage and frequent knee pain seems to be present because both pain and meniscal damage are related to osteoarthritis, and not because of a direct link between the two," study spokesperson Dr. Martin Englund, of Boston University School of Medicine, said in a prepared statement.
The menisci serve as cushions against joint cartilage degradation where the knee connect with the thigh and shin bones. Loss of meniscal function is a major risk factor for knee osteoarthritis. About 6 percent of middle-aged Americans, and between 11 percent and 15 percent of those aged 65 and older, have knee osteoarthritis.
For this study, researchers looked at people with knees (a total of 110) that had signs of knee osteoarthritis or were at high risk of developing knee osteoarthritis at baseline and developed frequent knee pain, stiffness or aching by the end of 15-month study. They were compared to a control group of people with knees (a total of 220) who had no frequent symptoms at baseline and did not develop any major knee problems during the study.
At the start of the study, meniscal damage was detected in 38 percent of case group knees and 29 percent of control group knees. Meniscal damage was more common in knees that had been operated on or suffered serious injury in the past.
There was a modest association between degree of meniscal damage and the development of frequent knee pain, aching and stiffness, but meniscal damage was most prevalent and pronounced in knees with clear evidence of osteoarthritis.
"Meniscal damage in older adults is highly associated with osteoarthritis of the knee. However, meniscal damage often seems not to be directly responsible for later symptoms, while other features of osteoarthritis may be so," Englund said.
The findings are published in the December issue of Arthritis & Rheumatism.
The American Academy of Family Physicians has more about knee osteoarthritis.
-- Robert Preidt
SOURCE: Arthritis & Rheumatism, news release, Nov. 26, 2007
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