Malnourished patients are more likely to have complications following total knee or hip replacement surgeries than morbidly obese patients,according to new research from researchers at the Perelman School of Medicine at the University of Pennsylvania. The findings are being presented at the American Academy of Orthopaedic Surgeons Annual Meeting in Las Vegas March 24-28. 

The Penn team examined 670 patients undergoing total knee or hip replacement. Twelve percent of the patients studied were malnourished, while nearly 19 percent were morbidly obese. Of the total patient population, 10 percent experienced a complication. The investigators found that when compared to patients with normal nutritional status, malnourished patients were nearly 20 percent more likely to have a postoperative complication, 13 percent more likely to be readmitted within 90 days of discharge, 12 percent more likely to have an ICU admission following surgery, and five percent more likely to require a return to the operating room.

“These findings can lead to the development of clear guidelines to identify which patients need remediation before undergoing total knee or hip replacement,” said lead investigator P. Maxwell Courtney, MD, a fourth-year orthopaedic surgery resident at the Perelman School of Medicine at the University of Pennsylvania. “While it would be beneficial for morbidly obese patients to lose weight for better overall health, our findings indicate that doing so is not necessarily indicative of a post-op complication.”

For the purposes of the study, malnourished patients were defined as having a pre-operative serum albumin level, a marker for adequate nutrition, of < 3.5 mg/dL. Morbidly obese patients were characterized by a pre-operative body mass index greater than 40 mg/kg2. Malnourishment so defined is independent of body weight. In fact, because of the greater volume of “empty calories” consumed, morbidly obese patients were more likely to be malnourished than non-morbidly-obese patients.

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