Hard on the knees

Arthritis sufferers are often advised to strengthen their quadriceps, the muscles at the front of the thigh, to ease knee pain and prevent arthritis from becoming worse. But for some people, such efforts may do more harm than good.

As part of a Northwestern University study, more than 200 senior citizens had knee X-rays, measurements of quadricep strength, and knee alignment assessments. Eighteen months later, the procedures were repeated. The researchers reasoned that if having strong quads was protective, then those who began the study with stronger muscles would have less progression of arthritis.

Instead, they found that the strength of the quadriceps was unrelated to worsening of arthritis. Even more surprising was the increased likelihood of arthritis progression in those with stronger quads who also were slightly bowlegged or knock-kneed or who had unstable knees.

“This puts a real glitch in the belief that strong quads delay arthritis progression,” says lead author Dr. Leena Sharma, associate professor of medicine at Northwestern’s Feinberg School of Medicine in Chicago. “Now we want to do exercise trials, looking at the structures of the knee before and after.”

Until those studies are done, Sharma says, people with arthritis should not just be given a handout of exercises to do on their own. They need the help of a physical therapist who can tailor a program to the person’s anatomy.

The study was published in the April 15 issue of the Annals of Internal Medicine.