1/27/10 Many people who have joint replacement surgery to fix worn out knees gain significant amounts of weight after their procedures, according to a surprising new study.
It has long been assumed that joint replacements help people waylaid by pain to be more active, increasing the odds of weight loss.
But researchers at the University of Delaware followed more than 100 knee replacement patients for two years and found that a majority gained an average of 14 more pounds than a control group who did not have surgery.
That’s even more than the 10 pounds most people gain when they quit smoking.
“Typically patients with end stage arthritis will say, 'Once I get my knee replaced the pain will go away and I’ll be able to exercise and I will lose weight.' So we were surprised there was any weight gain after surgery at all,” says Joseph Zeni, Jr., PhD, a physical therapist and research assistant professor at University of Delaware in Newark.
For the current study, researchers followed 106 adults with severe, painful knee osteoarthritis (OA) and 31 people without any knee pain.
Participants with osteoarthritis underwent knee replacement surgery and received outpatient physical therapy.
Two years later, two-thirds of the knee replacement patients had gained weight, regardless of their education level, marital status, income level or activity level prior to surgery. The control group did not experience any weight gain over that two-year period, suggesting that the extra pounds can’t be attributed to aging. The study was published in the journal Osteoarthritis and Cartilage.
And it doesn't appear to be an isolated result.
One 2006 study, for example, published in the journal Surgeon, found that a majority of people who were not obese before surgery had gained an average of 10 pounds three years after their joint replacement, and people who were obese before their joints were replaced gained even more – an average of 14 pounds in three years.
Weight gain is particularly dangerous for joint replacement patients because higher body mass has been identified as a risk factor for loosening of joint components, which can lead to the need for a revision surgery.
“People who had arthritis were much heavier to begin with and after surgery stayed heavier and continued to gain weight,” Zeni says.
Researchers did not track what participants were eating. But they did determine that functional ability improved, even though weight loss did not follow.
“We were surprised. Especially with the magnitude and really the percentage of the population that ends up gaining – which is most of them. It’s surprising,” says Lynn Snyder-Mackler, PhD, who co-authored the study.
She says one explanation for the findings may be the way doctors currently recommend knee replacements.
“The way total knee is approached right now is to tell patients to wait until you can’t stand it anymore to have your knee replaced and many times this means people are very sedentary for a very long time,” Snyder-Mackler says. “The curve to get back on the wagon and start exercising again takes a lot of time.”
She thinks it may be that patients stop exercising because of knee pain and then never get back into the habit after surgery.
Researchers say weight gain after knee surgery needs to be treated as an independent issue that requires nutrition and weight management education and patients need to be told that treating knee pain won’t automatically lead to weight loss.
“Surgeons think pain is the main problem and once it’s done, the knee doesn’t hurt so it’s fixed. But in fact there are lots of other things still wrong after that, largely as a consequence of having the disease for so long,” Snyder-Mackler says.
Dr. Lawrence Cheskin is the director of the Johns Hopkins Weight Management Center at the Bloomberg School of Public Health in Baltimore. He says this research would have even more of an impact if the scientists had looked at a different comparison group.
“Compare it to people who didn’t get their knee fixed,” Dr. Cheskin says. “Instead they’re comparing it to a group who is healthy and doesn’t have knee problems. Those groups are different because it may be there’s something about people with arthritis that they are more prone to gain weight whether their arthritis is treated with knee surgery or not.”
He does like that this study makes it clear that the medical community can’t expect that knee surgery will be the cure-all for weight problems among this group.
“It’s surprising that you have this fairly substantial weight gain. Fourteen pounds over two years sounds like too much. The average American adult gains a pound or two a year in middle age,” Dr. Cheskin says. “So this is clearly too much and it doesn’t make sense because you would think if your knee is better you’d be more active. But perhaps it indicates that these are people who won’t be doing exercise even if their knee doesn’t hurt.”
had a left tkr on Sept 8th 2011, I also had a manual manipulation under general anaesthetic about 6 weeks the original operation as the knee was very stiff. this has helped a bit. I have a 95 deg angle bend on the sore leg but does anybody know when and if you get used to this feeling of the new knee joint being so heavy, I doubt I will ever get back to anything near full mobility ever again. Ann-Marie
Point is: joint replacement surgery is a big deal and it takes a long time to recover.
bluestarmoon.wordpress.com
Still hurts and I am WONDERING HOW LONG IT USUALLY TAKES TO HEAL iT IS ALMOST 8 WEEKS.
Right now I am sorry I did this as it has affected my bad back.
I have had both knees replaced
and I feel great. They should have been done 10 years befor they were but now that they are done I feel great Admit I have gained some weight about 40 lbs but am trying to lose it now and have lost about 15 lbs and hope to lose another 50 or more I lived in a wheel chair for 10 years until I found a doctor that would do my knees every doctor I went to told me I would be crippled the rest of my life that was not an option for me or my husband so we kept looking and finelly found a doctor that would do them This is the best thing I have ever done and I would do it again in a heartbeat you just need the right doctor and a good attitude and a lot of family support
Cortisone shots in my knee are still working and I am doing well on 500 mg of Naproxsen a day.
We are warned about doing too much with the replaced joint and wearing it down too soon. And, that Revision surgery may not be successful.
I ride a bicycle, now down to 100 miles per week. After I've had two joints replaced, I figure won't be able to ride enough for fitness. That's about 4000 calories per week.
Swimming sounds good. But, experience is that it doesn't replace the bike and that the pool is frequently closed.
Richard
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