October 30, 2017
2 min read

Overweight, obese patients were less likely to lose weight after knee replacement

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Although overweight and obese patients who undergo knee replacement may lose weight in the period before and immediately following surgery, they are less likely to lose more than 2.5% of their body weight in the ensuing 1 year to 2 years, according to findings.

Using the Osteoarthritis Initiative, researchers assessed 210 overweight and obese patients (BMI≥25 kg/m2) who had knee OA on radiography and underwent a total or partial knee replacement. Participants were weighed at baseline and at follow-up visits. The researchers categorized the average annual weight changes during the 1-year to 2-year periods before, the period including and the period after knee replacement surgery. Annual changes were classified as a loss (≥ -2.5%), maintenance (> -2.5) or gain (≥ 2.5%). Most patients were white (84%), female (62%), had attained some post-high school education (80%) and had an income exceeding $50,000. Immediately preceding knee replacement, the mean patient age was 66.4 years and BMI was 31.4 ±3.4 kg/m2.

The researchers found that, on average, patients lost roughly 0.6 kg/year during the time period that encompassed the surgery, but gained 0.9 kg/year in the period following surgery. This resulted in an overall net weight gain (0.3 kg/year). Based on the classifications of unadjusted weight changes, researchers determined that time around the surgery was the only period in which more patients were classified as “loss” than “gain.”

Of patients who were seen for additional follow-up, further weight gain (0.3 kg/year) was observed. During the immediate postoperative time period, patients were significantly less likely to achieve consequential weight loss vs. the interval that included the knee replacement surgery (OR: 0.37).
In models adjusted for socioeconomic status (BMI, age, gender, race/ethnicity, education and income), health factors (comorbid conditions, high depressive symptoms, smoking, back pain, hip pain, ankle pain and foot pain) and knee-specific characteristics (severity, symptoms, pain and injury), patients had a higher likelihood of weight gain during both the preoperative and postoperative intervals vs. the time period that included the surgery.

“Between 22% and 33% of patients are gaining more than 2.5% of their body weight and are less likely to lose weight in the 1 [year] to 2 years after the surgery,” the researchers wrote. “The results highlight a significant need for the development of weight management interventions specifically for knee replacement populations to help prevent further weight gain in the years following surgery.”-by Jennifer Byrne


Disclosures: The authors report no relevant disclosures.