Attention Guest, if you are not a member of Fitness Geared - Body Building & Fitness Community, you have 1 new private message waiting, to view it you must fill out 
Thanks: 
Likes: 
Dislikes: 
Knee replacement linked to weight gain: study
Reply With Quote
TweetThis contradicts a study done at Mount Sinai in 2010 published in Orthopedics.
Therefore, in medicine, when studies conflict we have to compare the study design, which many times, affects the conclusions more so than the question you are asking.
This one was a retroperspective study looking at data and analyzing the "association" ( so may not be cause and effect) of having knee surgery and weight gain afterwards. The mount sinai trial began with patients who needed knee surgery and followed them prospectively ( going forward) rather than looking backward like retrospective data. The advantage of the latter is you try to control "confounding" variables right from the get go. In retrospective data, there may not be control of "confounding" variables. Don't get me wrong, associative data is how we found out how bad cigarettes are, without doing prospective, double blind,placebo controlled trials ( which would have been ethically distasteful). THe advantage of retrospective data is you can use greater number of subjects.
The mounta sinai study found the greatest weight loss occurred in a population that had BMI greater than 30 before the knee replacement and were mostly women. So the participants in the two trials were slightly different ( this is called selection bias). What I would tell my med students is that knee replacement has the potential to help a patient lose or gain weight, and we need to find a better way to "select" and predict what type of patients will benefit from knee replacement if the sole purpose is for weight loss. There is different data regarding outcomes dealling with pain control,...that is a whole diffferent lecture....
