Man pushing rock up hill
Before undergoing total knee or hip replacement surgery, it is important for osteoarthritis patients to be of a healthy weight in order to improve joint function in the long term.

“To our knowledge, no previous research study had examined late-life mobility outcomes among recipients of total joint replacement,” says Aladdin Shadyab, a postdoctoral rheumatology fellow at University of California, San Diego School of Medicine, and lead author of a study published in Arthritis Care & Research.

Shadyab and colleagues studied women ages 65 to 79, who had 1,867 total knee replacement surgeries and 944 total hip replacement surgeries. Follow up was up to 18 years, so that the women’s mobility status could be evaluated at age 85, and the researchers looked at body mass index, waist circumference, and waist-hip ratio.

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“Our findings suggest that obesity predicted poor mobility among recipients of total hip or knee replacements, highlighting the need to advise osteoarthritis patients to maintain healthy body weight before total joint replacement surgery,” Shadyab says.

The researchers found obesity increased the chance of death prior to age 85, and it also significantly increased (by more than fourfold) the likelihood of limitations on mobility.

“This research is important for physicians, because it suggests that despite undergoing total joint replacement surgery for osteoarthritis, a large proportion of women still reported poor mobility in late life,” Shadyab says.

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He and colleagues used body mass index as an overall indicator of obesity, while waist-hip ratio and waist circumference indicate “central obesity,” or visceral fat.

“Each of these obesity indicators has varying associations with various health outcomes, and for certain conditions, central obesity is a stronger indicator than overall obesity for risk of adverse health outcomes,” according to Shadyab.