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Weight Gain Likely for Many After Knee Replacement

shutterstock 92479945Even though good physical therapy after knee replacement can help complete the cycle of functional recovery and reduced pain symptoms among overweight patients, a recent report suggests that unless activity habits are modified, patients accustomed to inactivity as a way to cope with pain are likely to put extra weight right back on after surgery. In short, knee replacement surgery may actually increase the risk of weight gain.

Reuters reports that an analysis of nearly 1,000 medical records of nearly knee-replacement surgery patients revealed that 30% of them gained 5% or more of their body weight within 5 years after surgery. Why the counterintuitive results? According to some experts, Reuters reports, those who have spent years adapting to knee pain via a more relaxed lifestyle are not likely to automatically alter their patterns of activity once the pain is reduced.

“After knee replacement we get them stronger and moving better, but they don’t seem to take advantage of the functional gains” and become more active, says Joseph Zeni, a physical therapy professor at the University of Delaware, who reportedly was not part of the study.

Reuters reports that Zeni believes the phenomenon has to do with the fact that health care professionals may not address the behavioral modifications that have happened during the course of arthritis in the years prior to knee replacement surgery.

The goal of putting in a new knee is to alleviate pain and get people moving around more, but said his team had noticed that patients tended to gain weight after surgery.

To see whether this was common, Daniel Riddle, lead author of the new study and a professor at Virginia Commonwealth University, used a patient registry from the Mayo Clinic in Rochester, Minn, that provided data about 917 knee replacement patients before and after knee replacement procedures.

The researchers found that 5 years after surgery, 30% of patients had gained at least 5% of their weight at the time of the surgery. In contrast, the research showed that less than 20% of those in a comparison group of similar people who had not had surgery gained equivalent amounts of weight in the same period.
Part of the explanation for the weight gain the researchers observed could be the age at which patients get surgery, Riddle said. People in their 50s and 60s tend to gain weight anyway.

Still, in light of the lower rates of weight gain in the comparison group, which was also middle-aged and older, Riddle said something else might also be at work among knee surgery patients.
“There’s something going on in these patients that predisposes them above and beyond their peers to weight gain,” Riddle told Reuters Health.

To reduce postsurgical weight gain, Zeni observed that health care providers could encourage patients to take advantage of their ability to function better and get them to take on a more active lifestyle.

Riddle concurs that a sedentary lifestyle before knee replacement might linger after surgery. In the Reuters report, Riddle explained that it will be important to develop and study weight loss interventions for these patients, and to target them to those who are most at risk of getting heavier, like relatively younger patients in their 50s and 60s and those who have lost weight before knee surgery.

[Source: Reuters and Arthritis Care & Research]