for knee replacement surgery to provide better mobility and eliminate

pain. Under those conditions you would expect patients to be more active

following the surgery, and therefore to lose weight.</p><p>However, a new study suggests it doesn't work out that way in most

cases. Researchers Joseph Zeni and Lynn Snyder-Mackler at the University

of Delaware found that patients typically drop weight in the first few

weeks after total knee arthroplasty (TKA), but then the number on the

scale starts creeping upward, with an average weight gain of 14 pounds in

two years.

</p><p>The study, which was sponsored by the National Institutes of Health, is

reported in the online edition of Osteoarthritis and Cartilage, the

official journal of the Osteoarthritis Research Society International.

</p><p>The research involved 106 individuals with end-stage osteoarthritis who

had knee replacement surgery, and an age-matched, healthy control group of

31 subjects who did not have surgery. Height, weight, quadriceps strength,

and self-perceived functional ability were measured during an initial

visit to UD's Physical Therapy Clinic, and at a follow-up visit two years

later.

</p><p>"We saw a significant increase in body mass index (BMI) over two years

for the surgical group, but not the control group," said Zeni, a research

assistant professor at UD. "Sixty-six percent of the people in the

surgical group gained weight over the two years -- the average weight gain

was 14 pounds."

</p><p>Those who had the knee replacement surgery started out heavier and

ended heavier than the control group. The weaker the surgery patients

were, as measured by the strength of the quadriceps, the more weight they

gained, Zeni found.

</p><p>"These findings are making us re-think the component after total knee

surgery and of patients not being in a routine of moving around," said

Snyder-Mackler, Alumni Distinguished Professor of Physical Therapy at UD.

</p><p>She notes that it's critical that people not wait too long to have a

knee replaced because their functional level going into surgery typically

dictates their functional level after surgery.

</p><p>Gaining weight after one knee replacement is worrisome because it could

jeopardize the patient's other knee. Between 35-50 percent will have

surgery on the other side within 10 years, Snyder-Mackler said.

</p><p>The researchers note that weight gain after a knee replacement needs to

be treated as a separate concern and integrated into post-operative care

through a combination of approaches, including nutritional counseling to

help patients with portion control, and more emphasis on retraining

patients with new knees to walk normally.

</p><p>Why do knee replacement patients tend to put on pounds? Perhaps, the

researchers say, because some basic assumptions were wrong.

</p><p>"For physical therapists and surgeons, the common thinking is that

after a patient's knee has been replaced, that patient will be more

active," said Snyder-Mackler. "But the practices and habits these patients

developed to get around in the years prior to surgery are hard to break,

and often they don't take advantage of the functional gain once they get a

new knee."

</p><p>The researchers say the post operative routine needs to include

retraining to walk more normally and more systematically. Social habits,

as well as physical habits, need to be altered, they say.

</p><p>"We need to encourage more community participation," Snyder-Mackler

said. "If you're not getting out of the house, you won't gain the benefit.

We need people with new knees to get out there -- with the help of their

family, their friends, and the community at large." </p><img src="http://admatch-syndication.mochila.com/images/ad.gif?aid=68367575&bid=informcom" /></div><div id="copyright"><div>

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