Study overturns common assumption about knee replacements in morbidly obese individuals
November 11, 2012 in Arthritis & Rheumatism
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.
"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.
Provided by
Hospital for Special Surgery
-
Researchers identify impact of rheumatoid arthritis and lupus on joint replacement surgery outcomes
Nov 11, 2012 |
not rated yet |
0
-
Rheumatoid arthritis patients have low expectations after knee replacement surgery
Nov 06, 2011 |
not rated yet |
0
-
Knee replacement not an 'easy solution' for obese patients
Oct 24, 2012 |
not rated yet |
0
-
No justification for denying obese patients knee replacements
Jul 24, 2008 |
not rated yet |
0
-
Study examines outcomes of gastric bypass surgery in morbidly obese and superobese patients
Apr 20, 2009 |
not rated yet |
0
-
Motion perception revisited: High Phi effect challenges established motion perception assumptions
Apr 23, 2013 |
3 / 5 (2) |
2
-
Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update)
Apr 02, 2013 |
4.5 / 5 (11) |
5
-
The visual system as economist: Neural resource allocation in visual adaptation
Mar 30, 2013 |
5 / 5 (2) |
9
-
Separate lives: Neuronal and organismal lifespans decoupled
Mar 27, 2013 |
4.9 / 5 (8) |
0
-
Sizing things up: The evolutionary neurobiology of scale invariance
Feb 28, 2013 |
4.8 / 5 (10) |
14
-
Enthalpy of reaction
41 minutes ago
-
Harmonic oscillation problem -Dancing pot
1 hour ago
-
Ultracapacitor to power electromagnet?
2 hours ago
-
Confusion in Electro Statics
2 hours ago
-
simple gravity question
3 hours ago
-
I need help understanding the Fourier components of a square wave
5 hours ago
- More from Physics Forums - Classical Physics
More news stories
Blame your parents for bunion woes
A novel study reports that white men and women of European descent inherit common foot disorders, such as bunions (hallux valgus) and lesser toe deformities, including hammer or claw toe. Findings from the Framingham Foot ...
Arthritis & Rheumatism
6 hours ago |
not rated yet |
0
|
New theory on genesis of osteoarthritis comes with successful therapy in mice
Scientists at Johns Hopkins have turned their view of osteoarthritis (OA) inside out. Literally. Instead of seeing the painful degenerative disease as a problem primarily of the cartilage that cushions joints, ...
Arthritis & Rheumatism
20 hours ago |
4.8 / 5 (6) |
0
|
Ultrasound findings can improve classification of RA
(HealthDay)—Compared to clinical diagnosis of synovitis, ultrasound-detected synovitis provides either improved sensitivity or specificity when used with the American College of Rheumatology/European League ...
Arthritis & Rheumatism
May 15, 2013 |
not rated yet |
0
Strong genetic component of fibromyalgia suggested
(HealthDay)—A genome-wide linkage scan has identified the chromosome 17p11.2-q11.2 region as the susceptibility locus for fibromyalgia, according to research published in the April issue of Arthritis & ...
Arthritis & Rheumatism
May 11, 2013 |
not rated yet |
0
Discovery shows fat triggers rheumatoid arthritis
Scientists have discovered that fat cells in the knee secrete a protein linked to arthritis, a finding that paves the way for new gene therapies that could offer relief and mobility to millions worldwide.
Arthritis & Rheumatism
May 08, 2013 |
5 / 5 (5) |
0
|
Team finds mechanism linking key inflammatory marker to cancer
In a new study described in the journal Oncogene, researchers reveal how a key player in cell growth, immunity and the inflammatory response can be transformed into a primary contributor to tumor growth.
New study identifies risk factors for depression among COPD patients
Patients suffering from chronic obstructive pulmonary disease (COPD) typically suffer from depression more frequently than those without COPD, resulting in higher levels of disability and illness and increasing the overall ...
Inflammatory bowel disease raises risk of melanoma
Patients with inflammatory bowel disease (IBD) are at higher risk of melanoma, a form of skin cancer, report researchers at Mayo Clinic. Researchers found that IBD is associated with a 37 percent greater risk for the disease. ...
Pharmaceutical advances offer new options for health outcomes
Research presented at Digestive Disease Week (DDW) explores pharmaceutical advances for treating irritable bowel syndrome with diarrhea (IBS-D) and hepatitis C.
Stress test may help predict increased mortality risk in sleep apnea patients
Many studies have shown that men and women who suffer from obstructive sleep apnea (OSA) - a disorder that causes breathing to halt intermittently during sleep – have a higher mortality rate than those who do not have the ...
Source of infection affects hospital mortality in septic shock patients in the ICU
In ICU patients who have septic shock, the anatomic source of infection has a strong effect on the chances of survival, according to a new study from researchers in Canada.