Effects of Preoperative Oral Electrolyte-Carbohydrate Nutrition Supplement on Postoperative Outcomes in Elderly Patients Receiving Total Knee Arthroplasty: A Prospective Randomized Controlled Trial

Objective Patients undergoing total knee arthroplasty (TKA) were primarily geriatric, with high risk of postoperative electrolyte disorders and malnutrition. Randomized controlled trials regarding oral nutrition supplement (ONS) strategies in TKA was sparse. This study aimed to evaluate the efficacy of preoperative oral electrolyte-carbohydrate nutrition supplement (OECNS) on patients (aged >65 years) undergoing TKA. Methods From April 2019 to January 2020, 94 patients undergoing primary elective unilateral TKA in our hospital were considered in this prospective randomized controlled study. This study included patients aged over 65 years with ASA I-III, and excluded patients with electrolyte disorders, malnutrition, and comorbidities. The control group (control group) received meal nutrition supplements (preoperative 6 h [Pre 6h]) and water (Pre 2h), while OECNS group (intervention group) received meal nutrition supplements (Pre 6h) and OECNS (Pre 2). The Student's t test and chi(2) test was used. The primary outcomes were the patient-reported comfort indicators (PRCIs) including hunger, thirst, nausea, vomiting, weakness, pain, anxiety, and general comfort. The secondary outcomes included indicators of electrolyte, nutrition, functional scores, clinical results, and complications. Results The scores of preoperative hunger (0.43 +/- 0.10), pain (2.30 +/- 0.34), and anxiety (9.04 +/- 2.71) were significantly lower in OECNS group compared with control group (hunger, 1.19 +/- 0.21; pain, 3.79 +/- 0.26; anxiety, 11.21 +/- 3.02) (Pre 1h) (all p < 0.05) as well as the weakness score on the first postoperative day (POD1) (OECNS group 3.57 +/- 0.24; control group 5.15 +/- 0.29; p < 0.001). A higher level of Na + (OECNS group 140.54 +/- 3.39; control group 138.07 +/- 5.21; p = 0.008) and a reduced rate of hyponatremia (OECNS group 6.4%; control group 21.3%; p = 0.036) on POD1 were found. Moreover, the higher level of blood glucose (Post 2h) and reduced rates of abnormal blood glucose (Pre 2h, Post 6h) were verified in control group (all p < 0.05). There was no significant difference regarding the other outcomes. Conclusion The administration of OECNS significantly improved subjective comfort, electrolytes, and blood glucose without increasing the rates of complications in patients (aged over 65 years) undergoing TKA.