Knee "buckling" is common, arthritis or not

By Amy Norton

NEW YORK (Reuters Health) - Many middle-aged and older adults have problems with their knee "go outing" or "giving way" while walking or climbing stairs, even when they don't have knee arthritis, according to a study published Monday.

Researchers found that among more than 2,300 adults ages 36 to 94, 12 percent said they'd suffered knee buckling at least once in the past three months. The problem was more common in people with x-ray evidence of knee arthritis, but more than half of study participants with knee buckling had no signs of arthritis on x-ray.

The findings are published in the Annals of Internal Medicine.

Knee buckling is a significant problem for two reasons, according to Dr. David T. Felson, the study's lead author and a professor of medicine at Boston University School of Medicine.

"First of all, it causes falls and fractures," Felson told Reuters Health. In his study, 13 percent of people who reported knee buckling in the past three months said it had caused them to fall.

"It's also strongly associated with functional limitations," Felson said, explaining that when people know they have a vulnerable knee they tend to avoid activities that could make the joint "go out."

Half of study participants with knee buckling said they were limited, at least somewhat, in their daily activities.

Knee arthritis certainly plays a role in knee buckling, Felson said, as does knee pain in general, whatever the source. Buckling was "far more common," he and his colleagues report, among people with knee pain compared with their pain-free counterparts.