July 8, 2005

Shedding a pound may ease stress on arthritic knees

NEW YORK (Reuters Health) - For overweight people hobbled
by knee arthritis, losing even one pound can diminish the
stress the knees take with every step, a new study shows.

The study, of 142 overweight adults with knee arthritis,
found that for each pound participants were able to shed, there
was a 4-pound reduction in the force hitting their knees with
every stride they took while walking.

That, according to the researchers, means that dropping
just one pound would reduce the "load" on the knee joint enough
to translate into slower arthritis progression.

Excess weight can contribute to the both the development
and progression of knee osteoarthritis. The most common form of
arthritis, osteoarthritis occurs when the cartilage cushioning
the joints breaks down over time, causing inflammation, pain
and stiffness.

Experts recommend that overweight and obese adults with
knee arthritis lose weight and exercise to help manage the
condition. But whether weight loss actually slows the
progression of knee arthritis is not yet clear, Dr. Stephen P.
Messier of Wake Forest University in Winston-Salem, North
Carolina, and colleagues note in the journal Arthritis &

In their study, the team tried to gauge the effects weight
loss can have on arthritis patients' knee mechanics. The
participants, all older adults with disabling arthritis
symptoms, were part of a larger weight-loss study.

The researchers performed a "gait analysis" of each patient
at the beginning of the study, and 6 and 18 months later. As
mentioned, they found that for each pound participants lost
during that time, there was a four-fold greater reduction in
the force going into the knee with each step they took.

"Accumulated over thousands of steps per day," the
investigators write, "a reduction of this magnitude would
appear to be clinically meaningful."

A "critical question," they add, is whether such
weight-loss effects hold up over time, and whether they can
slow the progression of knee arthritis.

SOURCE: Arthritis & Rheumatism, July 2005.