Background: This study investigates the effects of preoperative carbohydrate-rich drinks on postoperative outcomes after primary total knee arthroplasty. Methods: We prospectively randomized 153 consecutive patients undergoing primary total knee arthroplasty at one institution. Patients were assigned to one of three groups: group A (50 patients) received a carbohydrate-rich drink; group B (51 patients) received a placebo drink; and group C (52 patients) did not receive a drink (control). All healthcare personnel and patients were blinded to group allocation. Controlling for demographics, we analyzed the rate of postoperative nausea and vomiting, length of stay, opiate consumption, pain scores, serum glucose, adverse events, and intraoperative and postoperative fluid intake. Results: Demographics and comorbidities were similar among the groups. There were no significant differences in surgical interventions or experience. Surgical fluid intake and total blood loss were similar among the three groups (P = 0.47, P = 0.23). Furthermore, acute postoperative outcomes (ie, pain, episodes of nausea, and length of stay) were similar across all three groups. There were no significant differences in adverse events between the three groups (P = 0.13). There was a significant difference in one-time postoperative bolus between the three groups (P = 0.02), but after multivariate analysis, it did not demonstrate significance. None of the intervention group were readmitted, whereas 5.9% and 11.5% were readmitted in the placebo and control groups, respectively (P = 0.047). The chance of 90-day readmission was reduced in group A compared with group C (odds ratio, 0.08; 95% confidence interval, 0.01 to 0.72; P = 0.02). There were no differences in other postoperative outcome measurements. Conclusion: This randomized controlled trial demonstrated that preoperative carbohydrate loading does not improve immediate postoperative outcomes, such as nausea and vomiting; however, it demonstrated that consuming fluid preoperatively proved no increased risk of adverse outcomes and there was a trend toward decrease of one-time boluses postoperatively. Clinical Trials Registry: NCT03380754

Objectives: Individuals with knee osteoarthritis (KOA) experience both pain and functional limitations that negatively impact quality of life and contribute to years lived with disability. Movement-evoked pain (MEP) is thought to act as a barrier to participation in daily activities, resulting in reduced function. The aim of this study was to examine the relationships between knee-specific measures of self-reported pain interference, fear avoidance, and performance-based MEP and their associations with physical function among individuals with KOA seeking joint arthroplasty. Methods: Using baseline data from the Acute to Chronic Pain Signatures Consortium (training data: release 1.0.0, n=603; validation data: release 2.0.0, n=441), this cross-sectional study used structural equation modeling to examine associations among self-reported pain, movement-evoked pain, and physical function. We further evaluated whether these relationships differed by task specificity and biological sex. Results: Greater self-reported knee pain interference and higher fear avoidance were associated with poorer physical function ( β =−0.83, P <0.001). In contrast to expectations, MEP showed little association with physical function ( β =−0.11, P =0.072) and was weakly associated with self-report knee pain interference and fear avoidance ( β =0.36, P <0.001). These patterns were consistent in a validation dataset. Discussion: These findings suggest knee-specific self-report measures (pain, pain interference, and fear avoidance) and performance-based MEP are unique constructs. Self-report measures of knee pain interference and fear avoidance were more strongly related to the functional limitations in KOA compared with to performance-based MEP.