For adults with severe obesity who need total knee replacement, having another surgery first — bariatric (weight-loss) surgery — may improve knee replacement outcomes or even make knee replacement unnecessary, according to a new study published in the journal JAMA Network Open.
Bariatric surgery cam take several different forms. One of the most common procedures is gastric bypass, in which the pathway of the digestive system is rerouted to bypass most of the stomach and the upper part of the intestines. Other procedures include sleeve gastrectomy, in which the stomach is reduced to a narrow sleeve, and gastric banding, in which a device is implanted to restrict the functional size of the stomach. Several studies have found that gastric bypass appears to offer the greatest weight-loss and metabolic benefits for people with type 2 diabetes, compared with sleeve gastrectomy or gastric banding. In people eligible for the surgery, undergoing gastric bypass has been linked to better health outcomes, lower healthcare costs, and a longer life. And in people with type 2 diabetes, weight loss from bariatric surgery is linked to diabetes remission — meaning that a person has normal blood glucose levels without taking any glucose-lowering drugs. This remission, in turn, is linked to numerous health benefits, including a lower cancer risk.
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For the latest study, 82 adults ages 65 and younger with severe obesity — all of whom were classified as needing total knee replacement — were randomly assigned either to undergo bariatric surgery, or to proceed with their normal treatment. Normal treatment meant choosing to go through with the total knee replacement for nearly all participants in this group. Among all participants, over 80% were women, and the average age was about 58. Participants’ average body-mass index (BMI, a measure of body weight that takes height into account) was 43.8, which is well into the category of severe obesity.
Out of the 41 participants who were assigned to have bariatric surgery, 39 (95%) underwent gastric banding. Within this group, 29 participants (71%) also later underwent total knee replacement. Out of the 41 participants who were assigned to proceed with treatment as usual, 39 (95%) underwent total knee replacement. The researchers were interested in comparing outcomes over at least a year following knee replacement in these two groups — including whether participants experienced death from any cause, complications resulting in a delayed hospital discharge, unplanned hospital or clinic procedures, or readmission to the hospital.
Fewer knee-replacement surgeries needed among bariatric surgery group
The researchers found that over a median follow-up period of 27 months, six participants in the group assigned to bariatric surgery (15%) experienced at least one of the poor outcomes listed above. In the group assigned to treatment as usual, 15 participants (37%) experienced at least one of these outcomes. When it came to weight loss, 12 months after participants either underwent bariatric surgery or didn’t, the group assigned to bariatric surgery had an average BMI that was 6.32 units lower than the group that wasn’t assigned to bariatric surgery. What’s more, 12 members of the bariatric surgery group (29%) decided not to undergo total knee replacement because their symptoms improved following bariatric surgery — compared with only two members of the group not assigned to bariatric surgery (5%) who decided not to undergo total knee replacement.
The researchers concluded that in adults with severe obesity who are judged to need total knee replacement, undergoing bariatric surgery first may reduce the risk of complications associated with knee replacement surgery — or possibly even improve knee-related symptoms enough that knee replacement is no longer urgently needed. They noted that this study could help settle the question of whether bariatric surgery is a good idea for people with severe obesity and advanced knee osteoarthritis.
Want to learn more about bariatric surgery and diabetes? Read “Is Bariatric Surgery for You?” and “Bariatric Surgery and Diabetes: Questions and Answers.”
Want to learn more about joint pain? Read “14 Ways to Reduce Joint Pain With Diabetes.”