Weight Loss Before Knee Replacement Improves Some Outcomes in Severely Obese Patients
August 23, 2019

In patients with morbid obesity, losing about 9 kg (20 lbs) before total knee arthroplasty improves postoperative outcomes, according to a study published in the Journal of Bone & Joint Surgery.

“Losing at least 20 pounds was associated with lower absolute length of stay, lower odds of extended length of stay, and lower odds of being discharged to a facility,” said David S. Jevsevar, MD, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire.

The study was designed to assess the benefits of weight loss before total knee arthroplasty in patients with a body mass index (BMI) of ≥40 kg/m2.

“Many surgeons require or request weight loss among morbidly obese patients before total knee arthroplasty,” the authors noted.

That concern reflects consistent evidence showing increased rates of adverse outcomes in this patient population.

Dr. Jevsevar and colleagues reviewed data on 203 morbidly obese patients who underwent total knee arthroplasty between 2011 and 2016 at 1 medical centre. This group accounted for 13.5% of approximately 1,500 patients who underwent knee replacement during that time.

In the months before the procedure, 41% of patients lost at least 2.3 kg (5 lbs), 29% lost at least 4.5 kg (10 lbs), and 14% lost at least 9 kg (20 lbs). The researchers compared the outcomes of each preoperative weight-loss group with those of patients who did not lose weight.

Several outcomes were improved in patients who lost the most weight, but not in those who lost 2 to 4.5 kg. After adjusting for other factors, the researchers found that patients who lost at least 9 kg spent about 1 less day in the hospital and were 76% less likely to have an extended hospital stay of 4 days or longer. Weight loss of at least 9 kg was also associated with a 72% reduction in the odds of being discharged from the hospital to a facility.

Preoperative weight loss was not associated with change in operative time or with postoperative improvement in physical health and function. Length of hospital stay and operative time were significantly increased for patients who gained weight before surgery.

Although morbid obesity is associated with increased surgical risk, it remains unclear whether preoperative weight loss can improve outcomes following total knee arthroplasty. The authors noted that larger, multicentre studies are needed to confirm their findings.

Reference: https://doi.org/10.2106/JBJS.18.01136

SOURCE: Wolters Kluwer