Stronger Leg Muscles Can Protect Against Knee Osteoarthritis

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Stronger Leg Muscles Can Protect Against Knee Osteoarthritis

http://www.sciencedaily.com/releases/2006/11/061116100945.htm

Stronger quadriceps muscles in the legs can help protect against

cartilage loss behind the kneecap, according to Mayo Clinic

researchers presenting preliminary study data at the American

College of Rheumatology Annual Meeting on Nov. 15.

Knee osteoarthritis (OA) occurs when the cartilage that cushions the

ends of the bones in the knee joint deteriorates over time. As this

cushion wears down, the joint doesn't function as well and may be

painful.

Mayo researchers, in collaboration with researchers from Boston

University and the University of California, San Francisco, studied

265 men and women diagnosed with knee OA. They performed magnetic

resonance images (MRIs) of participants' knee joints at the

beginning of the study and again at 15 months and 30 months. Based

on these MRIs, researchers determined how much cartilage loss

occurred over time at the two joints of the knee: the tibiofemoral

joint, where the thigh bone (femur) meets the lower leg bone

(tibia); and the patellofemoral joint, behind the kneecap (patella).

When the study began, researchers also had measured the strength of

participants' quadriceps muscles (leg muscles in the upper thigh).

Analyzing these measurements, researchers observed that participants

who had greater quadriceps strength had less cartilage loss within

the lateral compartment of the patellofemoral joint, which is

frequently affected by OA.

" A stronger quadriceps muscle helps keep the patella from moving

laterally and tracking abnormally with movement, " says Shreyasee

Amin, M.D., Mayo rheumatologist and the study's lead

researcher. " Our study results emphasize that it's important to

encourage people with knee osteoarthritis to maintain strong

quadriceps muscles as recommended by their physician. "

The exact cause of OA isn't known. Researchers suspect a combination

of factors, including being overweight, the aging process, joint

injury or stress, heredity and muscle weakness. Pain is the major

complication of OA. The degree of pain can vary greatly, from mild

inconvenience to a debilitating condition that interferes with daily

activities.

Other members of this Mayo-led research team included:

Baker, Ph.D., Jingbo Niu, M.D.; D.Sc., Joyce Goggins; Hunter,

M.B.B.S., Ph.D.; and Felson, M.D., all from Boston University;

and Ali Guermazi, M.D.; Mikayel Grigoryan, M.D.; both from the

University of California, San Francisco. This work was supported by

grants from the Arthritis Foundation, the National Institutes of

Health and the Bayer Corporation.

Note: This story has been adapted from a news release issued by Mayo

Clinic.