Buckling knees affect even the healthy
People who have arthritis or who have had knee surgery often have a knee give way without warning. But researchers reported on Monday that sudden buckling was fairly common even among people with no known knee problems.
Writing in The Annals of Internal Medicine, the researchers said a study of more than 2,300 people middle age and older found that 12 percent had knee buckles in the previous three months. And more than 1 out of 10 times, the buckling led to falls.
In most cases, the problem occurred as people walked or went up or down stairs. So shifting weight appears to play a role, said the researchers, who were led by Dr. David T Felson of the Boston University School of Medicine.
But why otherwise healthy knees give way is still not understood.
The researchers did point to several possible contributing factors, among them weight. Seventeen percent of the heaviest people in the study reported buckling, while 7 percent of the lightest ones did.
Other research has suggested that muscle weakness, especially in the quadriceps, may play a role. A sudden change in the angle of knee flexion may also contribute.
In people with arthritis, the tendency toward knee buckling and falls may explain why they are at higher risk for fractured hips, even when their hipbone density is not a problem, the study said.
New scanner for multiple sclerosis
A machine that can quickly assess the state of nerve fibers in the retina may offer a better way to measure the progression of multiple sclerosis than the MRI examinations now used, researchers said Monday.
Writing in Neurology, the researchers said the machine used a method known as optical coherence tomography to measure the thickness of the nerve fibers, which shrink as multiple sclerosis progresses.
The lead author of the study, Dr Peter Calabresi of Johns Hopkins, said the problem with MRI scans for multiple sclerosis patients was that they measured brain shrinkage, a symptom that tends to occur in the later stages of the disease.
