February 01, 2017
2 min read

Patients who are obese may have satisfactory in-hospital outcomes after TKA

The length of hospital stays was shorter and transfusion rates were lower among obese and morbidly obese patients following total knee arthroplasty.

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Patients who are obese may experience satisfactory in-hospital outcomes after primary total knee arthroplasty when the right measures and precautions are used, based on a recently published study.

“[Obese] patients will do as well as a person of normal size despite the obesity and, surprisingly, the obese and morbidly obese patients might, in some circumstances, do better than the normal-weighted person,” Wayne M. Goldstein, MD, professor of clinical orthopedics at the University of Illinois at Chicago College of Medicine and chairman of the Department of Orthopedic Surgery at Advocate Lutheran General Hospital in Morton Grove, Ill., USA, told Orthopaedics Today Europe. Goldstein was one of the authors of the study.

“It could be because they are younger, or it could be because they have less bleeding because they have a lot of adipose tissue putting pressure on the knee and stopping the bleeding,” Goldstein said.

TKA in obese patients

Goldstein and colleagues used the National Hospital Discharge Survey national database to identify patients who underwent primary total knee arthroplasty (TKA) from 2001 to 2010. Of those patients, 29,271 patients were not obese; 2,645 patients were obese; and 1,150 patients were morbidly obese.

Results showed an increase in the number of patients who underwent TKA in all groups with time, as well as a strong correlation between the rate of obesity/morbid obesity with time.

Compared with patients who were not obese, researchers found patients who were obese and morbidly obese were more likely to be women, younger, and to have diabetes and Medicaid. Patients who were obese and morbidly obese had a shorter length of stay and lower transfusion rates, according to results. Researchers noted obese patients had higher discharge to home rates and lower rehabilitation discharge rates compared with patients who were nonobese or morbidly obese.

Geographic variations in obesity rates

Results of the analysis showed a significant variation in the rates of patients who were obese and undergoing TKA based on U.S. geographic location. The highest rates of obesity and morbid obesity were found in the Midwest, and the West region had the lowest rates of obese and morbidly obese patients scheduled for TKA.


Subgroup analysis showed Medicare payer status was a significant factor among patients who were not obese. There was a difference in length of stay between patients with and without Medicare who were not obese, but there was no difference in length of stay between patients with and without Medicare who were obese or morbidly obese. Researchers noted patients with Medicaid who were not obese were less likely to be discharged to care facilities. However, researchers found no difference among patients who were obese or morbidly obese according to their Medicaid status.

Change in management suggested

Despite previous research that showed positive results following TKA in patients who were obese, Goldstein noted he was surprised by the magnitude of obesity among total joint patients. He noted surgeons need to change their management protocols for patients who are obese to ensure proper treatment, which includes adding staff members to assist with the surgical procedure.

“We have had to change how we manage things, like we used to give a set dose of antibiotics to everybody, but now the antibiotics are based off of body weight,” Goldstein said. “We have learned how to mobilize and get patients walking immediately. We used to have them lay in bed for 5 days so they would not bleed, and then people would die [from] blood clots. Now that they walk immediately, that is not the issue.” – by Casey Tingle

Disclosure: Goldstein reports no relevant financial disclosures.