Featured Research

from universities, journals, and other organizations

Study overturns common assumption about knee replacements in morbidly obese individuals

Date:
November 11, 2012
Source:
Hospital for Special Surgery
Summary:
After total knee replacement (TKR) surgery, patients who are morbidly obese have similar pain and function outcomes as patients who do not fall into this weight category, according to a new study.

After total knee replacement (TKR) surgery, patients who are morbidly obese have similar pain and function outcomes as patients who do not fall into this weight category, according to a new study by researchers at Hospital for Special Surgery. The finding is surprising given that numerous studies have shown that obese patients have worse outcomes. The study will be reported at the annual meeting of the American College of Rheumatology/Association of Rheumatology Health Professionals, to be held Nov. 9-14, in Washington D.C.

Related Articles


"As long as they are medically appropriate for surgery, even obese people can have excellent results from joint replacement. Obesity, in and of itself, should not be viewed as an absolute contraindication to joint replacement," said Lisa Mandl, M.D., M.P.H.., a rheumatologist at Hospital for Special Surgery (HSS), in New York City, who was involved with the study.

"We undertook the study because we are in the midst of an obesity epidemic," said Susan Goodman, M.D., a rheumatologist at HSS, who led the study. Until now, many studies examining TKRs in obese patients have lumped all patients with a body mass index (BMI) of 30 and higher into one category. "In my mind, there is clearly a difference in a patient with a BMI of 40, the morbidly obese, versus an obese patient with a BMI of 33," said Dr. Goodman. "We wanted to see if we could identify a difference in outcomes among those patients, and we found that the morbidly obese had just as good outcomes." Overweight individuals are prone to developing osteoarthritis because the extra weight adds extra wear and tear on joints. An obese individual often requires a TKR decades before a patient who is of normal weight will require one.

To conduct their research, the HSS researchers turned to the HSS Total Joint Replacement Registry, a prospective registry started in 2007 that includes, among other things, data on all patients who seek care at HSS for knee replacement surgery. They identified all patients with a BMI greater than 18.5 who had undergone a TKR between July 2007 and June 2009. Patient pain and function had been assessed prior to surgery and two years after surgery using the Western Ontario and McMaster Universities Arthritis Index (WOMAC). The WOMAC measures pain, stiffness, and functional limitation. It is one of the more widely used tools for measuring outcomes after TKR.

The investigators found that two years after surgery, pain and function scores improved across all BMI categories and as BMI rose, patient improvements increased. Patients with a BMI greater than 40 showed the most improvement.

"The morbidly obese did well in terms of their pain and function outcomes. They start out in a much worse situation and then by two years, they are pretty much caught up," said Dr. Goodman. "I was surprised, because my expectation was that they wouldn't do as well, their functional outcomes wouldn't be as good, and they wouldn't be as satisfied. But, it turns out that they were really quite satisfied."

Dr. Goodman said that many surgeons have concerns about performing knee replacements in the morbidly obese. Almost 90% of referring physicians believe that obesity increases the likelihood of poor outcomes after a TKR.

"There is no question that the morbidly obese are a more difficult group to manage -- they are more likely to have a significant number of comorbidities, including cardiac disease," said Dr. Goodman. "If you look at the Deyo comorbidity scale of the patients in our study, the morbidly obese had a significantly greater number of comorbidities than normal, so they were definitely sicker to start with, but their outcomes were just as good."

In a multivariate analysis, the researchers identified a number of other factors that correlated with pain outcomes after surgery. They found that individuals who were Caucasian experienced less pain, and individuals who were female or had only a high school education had worse pain and function two years after surgery. Patients who were between the ages of 61 to 70 had less pain than those who were younger than 60. The researchers say that more research is needed to flush out why these factors play a role in recovery.

"It's surprising to learn that a patient's level of education has a greater influence on their outcome and satisfaction than obesity does," said Mark Figgie, M.D., an orthopedic surgeon and Chief of the Surgical Arthritis Service at HSS.

The study was supported by a Centers for Education and Research on Therapeutics grant from Agency for Healthcare Research and Quality. Other Hospital for Special Surgery authors involved in the study include Alejandro Gonzalez Della Valle, M.D.


Story Source:

The above story is based on materials provided by Hospital for Special Surgery. Note: Materials may be edited for content and length.


Cite This Page:

Hospital for Special Surgery. "Study overturns common assumption about knee replacements in morbidly obese individuals." ScienceDaily. ScienceDaily, 11 November 2012. <www.sciencedaily.com/releases/2012/11/121111153612.htm>.
Hospital for Special Surgery. (2012, November 11). Study overturns common assumption about knee replacements in morbidly obese individuals. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2012/11/121111153612.htm
Hospital for Special Surgery. "Study overturns common assumption about knee replacements in morbidly obese individuals." ScienceDaily. www.sciencedaily.com/releases/2012/11/121111153612.htm (accessed October 25, 2014).

Share This



More Health & Medicine News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
WHO: Millions of Ebola Vaccine Doses by 2015

WHO: Millions of Ebola Vaccine Doses by 2015

AP (Oct. 24, 2014) The World Health Organization said on Friday that millions of doses of two experimental Ebola vaccines could be ready for use in 2015 and five more experimental vaccines would start being tested in March. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Doctor in NYC Quarantined With Ebola

Doctor in NYC Quarantined With Ebola

AP (Oct. 24, 2014) An emergency room doctor who recently returned to the city after treating Ebola patients in West Africa has tested positive for the virus. He's quarantined in a hospital. (Oct. 24) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins