Obesity alone may not affect knee replacement outcome or increase overall complication risk
Obesity alone may not diminish outcomes or increase the risk of complications in total knee replacement (TKR) patients, according to two research studies presented today at the 2013 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS). However, TKR replacement patients may face significantly longer hospital stays and related costs.
Total knee replacement in obese patients previously has been associated with increased post-operative complications and lower clinical function scores in multiple research studies.
In the study, "The Effect of Obesity on Direct Medical Costs in Total Knee Arthroplasty (TKA)" researchers reviewed the records of more than 8,000 patients who had undergone single, primary or revision TKR procedures between 2000 and 2008, collecting data on clinical and surgical characteristics, complications and hospital costs. Patients were classified into eight groups based on body mass index (BMI) and comorbidities (diabetes, hypertension, etc.).
Length of hospital stay and direct medical costs were lowest for patients with a BMI of 25-30kg/m2. Greater BMI was associated with significantly longer hospital stays after adjusting for age, sex, type of surgery and comorbidities. Every 5 unit increase in BMI beyond 30 kg/m2 was associated with approximately $250-$300 in higher hospitalization costs for primary knee arthroplasty and $600-$650 higher hospitalization costs for revision procedures.
Although increasing BMI was not associated with an overall increase in complication risk during the 90-day window, there was a higher rate of infection in obese patients.
"The costs associated with obesity are believed to be largely those that come from managing comorbid medical conditions linked to obesity, such as diabetes," said lead study author Hilal Maradit-Kremers, MD, an associate professor of epidemiology at Mayo Clinic in Rochester, Minn. In this study, "we attempted to tackle this problem by restricting the analysis to patients without comorbid conditions. Even in the absence of comorbidities, obesity was still associated with longer stays and higher hospital costs."
"The bottom line is that obesity is increasingly common among patients undergoing joint replacement and it creates a myriad of technical and medical challenges, and likely contributes to the financial burden of the surgery," said senior author David G. Lewallen, MD, an orthopaedic surgeon, also from Mayo Clinic.
In the related study, "Outcome of Total Knee Arthroplasty in Obese Patients," researchers in Singapore analyzed the outcomes of 301 TKA patients between December 2008 and April 2010 and grouped them according to BMI.
There was no difference in surgical time between obese and non-obese patients, although the obese patients had a longer hospital stay following TKR – 7.77 days versus 6.29 days for non-obese patients.
Patient outcomes were recorded pre-operatively and at 2 years after TKR using Knee Society Score (KSS), Short Form 36 Health Survey (SF36) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) outcomes.
The non-obese patients achieved "superior" post-operative flexion (ability to bend) and range of movement. The absolute improvements in WOMAC scores among the obese patients post surgery also were deemed statistically superior and comparable to those of non-obese patients.
The study concluded that TKR is a "safe and efficacious operation in obese patients with no significantly greater risk of complication."
"Obesity does not negate good surgical outcome in total knee arthroplasty," said lead study author Chin Tat Lim, MD.
Provided by American Academy of Orthopaedic Surgeons
- Knee replacement not an 'easy solution' for obese patients Oct 24, 2012 | not rated yet | 0
- Study overturns common assumption about knee replacements in morbidly obese individuals Nov 11, 2012 | not rated yet | 0
- Post surgical phone support improves outcome following knee replacement Feb 07, 2012 | not rated yet | 0
- Shorter hospital stay for knee replacement linked with greater revision, mortality risks Feb 09, 2012 | not rated yet | 0
- No justification for denying obese patients knee replacements Jul 24, 2008 | 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
latitude & longitude & air pressure
1 hour ago Hi there, I have a peculiar question. Imagine that you are in a earth position, obtained by google, that gives you the latitude and longitude....
Differences of Classical Mechanics when learned with Calc vs algebra?
4 hours ago what are the differences? Every example I find usually has a derivative or integral or some kind of calculus defined concept that seems to make it...
what is the distance traveled
8 hours ago Hi. I have newly started to study mechanical physics. based on study, I conduct a simple experiment. But unfortunately i am unable apply the laws in...
Image of a Convex Lens Cut in Half Horizontally
12 hours ago Hello everyone, A friend of mine came up with this question in class and I really do not have a good answer. Suppose you have a convex lens...
Ray tracing throught optical system of thick lenses
13 hours ago Can you advise me a free software that allow to draw rays passed throught system of thick lenses (preferable in 3D)?
Faraday's law on circular wire
13 hours ago In my examples on Faraday's law in my book, they use a drawing of a magnet approaching a circular wire. The changing magnetic flux then induces an...
- More from Physics Forums - Classical Physics
More news stories
Johns Hopkins researchers have developed new guidelines—the first in more than 35 years—to govern the amount of blood ordered for surgical patients. The recommendations, based on a lengthy study of blood use at The Johns ...
Surgery 8 hours ago | not rated yet | 0
Indian doctors said Wednesday they have successfully carried out a first round of reconstructive surgery on the skull of a baby suffering from a rare disorder that caused her head to nearly double in size.
Surgery 12 hours ago | not rated yet | 0
A 33-year-old Polish man received a face transplant just three weeks after being disfigured in a workplace accident, in what his doctors said Wednesday is the fastest time frame to date for such an operation. ...
Surgery 13 hours ago | not rated yet | 0
Surgeons investigated sexual function in 62 patients, 50 years and older, who had received extensive spinal–pelvic instrumentation for spinal deformity at the University of Virginia Health Center. Based on their results, ...
Surgery May 21, 2013 | not rated yet | 0
Physicians at Monash University and The Alfred Hospital in Melbourne, Australia describe the logistic, medical, and societal challenges faced in treating spine trauma in morbidly obese patients. Based on a case series of ...
Surgery May 21, 2013 | not rated yet | 0
Swiss scientists reveal the mechanism responsible for aging hidden deep within mitochondria—and dramatically slow it down in worms by administering antibiotics to the young.
8 hours ago | 4.8 / 5 (4) | 0 |
Researchers from Queen Mary, University of London have led the largest sequencing study of human disease to date, investigating the genetic basis of six autoimmune diseases.
8 hours ago | not rated yet | 0 |
Until now, little was scientifically known about the human potential to cultivate compassion—the emotional state of caring for people who are suffering in a way that motivates altruistic behavior.
5 hours ago | 5 / 5 (1) | 2 |
(HealthDay)—Migraines and depression can each cause a great deal of suffering, but new research indicates the combination of the two may be linked to something else entirely—a smaller brain.
5 hours ago | 5 / 5 (1) | 0 |
A new approach for immunizing against influenza elicited a more potent immune response and broader protection than the currently licensed seasonal influenza vaccines when tested in mice and ferrets. The vaccine ...
6 hours ago | not rated yet | 0 |
In a series of lab experiments designed to unravel the workings of a key enzyme widely considered a possible trigger of rheumatoid arthritis, researchers at Johns Hopkins have found that in the most severe ...
7 hours ago | 5 / 5 (1) | 0 |