For a study, researchers sought to determine the impact of carbohydrate-rich beverages before surgery on postoperative outcomes following primary total knee arthroplasty. They randomly assigned 153 consecutive patients receiving primary total knee arthroplasty at one institution to one of two groups. Patients were divided into three groups: group A (50 patients) got a carbohydrate-rich drink, group B (51 patients) received a placebo drink, and group C (52 patients) received no drink (control). The group assignment was concealed from all healthcare professionals and patients. They looked at the rate of postoperative nausea and vomiting, duration of stay, opiate use, pain ratings, blood glucose, adverse events, and intraoperative and postoperative fluid intake after controlling for demographics.

The groups had comparable demographics and comorbidities. There were no statistically significant changes in surgical procedures or experience. The three groups had similar surgical fluid intake and total blood loss (P=0.47, P=0.23). Furthermore, the immediate postoperative outcomes (pain, nausea, and duration of stay) were comparable across all three groups. There were no statistically significant differences in adverse events across the three groups (P=0.13). There was a significant difference in one-time postoperative bolus between the three groups (P=0.02). However, this did not hold up after multivariate analysis. There were no readmissions in the intervention group but 5.9% and 11.5% in the placebo and control groups, respectively (P=0.047). Group A had a lower likelihood of 90-day readmission than group C (odds ratio, 0.08; 95% CI, 0.01 to 0.72; P=0.02). Other surgical outcome assessments revealed no differences.

The randomized controlled trial found that preoperative carbohydrate loading does not improve immediate postoperative outcomes like nausea and vomiting; however, it found that drinking fluid before surgery did not increase the risk of negative outcomes, and there was a trend toward fewer one-time boluses after surgery.