A Comparison of the ERAS Protocol Including Oral Carbohydrate Supplementation versus the Traditional NPO Approach in Patients Undergoing Total Knee Arthroplasty

To compare the effects of the Enhanced Recovery After Surgery protocol with preoperative oral carbohydrate supplementation versus the traditional nil per os fasting method on postoperative pain and opioid consumption in patients undergoing total knee arthroplasty .

Randomized, parallel, single-center trial. N=78 (39/group). Computer-generated block randomization (4,6), sealed envelopes. Outcome assessor blinded.

Single-center trial in operating rooms and orthopedic wards of teaching hospitals of Ahvaz Jundishapur University of Medical Sciences, Iran. Patients undergoing elective total knee arthroplasty receive either the Enhanced Recovery After Surgery protocol with a preoperative carbohydrate drink or traditional nil per os fasting. Participants and care providers are not blinded; the outcome assessor is blinded to group allocation.

Inclusion criteria: Adults aged 18 years or older; American Society of Anesthesiologists physical status I–III; scheduled for elective total knee arthroplasty ; able to provide informed consent; able to take oral fluids. Exclusion criteria: Emergency or urgent knee surgery (e.g., surgery for knee fractures or acute conditions); uncontrolled diabetes; severe cardiovascular, renal, or hepatic disease; gastrointestinal disorders or malabsorption preventing oral intake; allergy to carbohydrate solution.

ERAS group: carbohydrate drink 2h preop plus ERAS protocol. NPO group: standard fasting and conventional care.

Postoperative pain intensity; postoperative opioid consumption.

Method of randomization: Block randomization with variable block sizes of 4 and 6. Unit of randomization: Individual patients. Randomization strata: None (no stratified randomization was used). Tools used in randomization: The random allocation sequence was generated using Sealed Envelope, a secure online randomization service designed for clinical trials. The software was set to produce permuted blocks of sizes 4 and 6. How the random sequence was built: The principal investigator configured the Sealed Envelope system with two treatment arms (ERAS with carbohydrate supplementation and traditional NPO) and variable block sizes (4 and 6). The software then generated a randomization list with sequential subject numbers. The list was exported and used to prepare the allocation envelopes. Allocation concealment: Sequentially numbered, opaque, sealed envelopes were prepared by an independent person not involved in patient enrollment. The envelopes were prepared according to the randomization list generated by Sealed Envelope. Each envelope was opened only after the patient was confirmed eligible and had provided written informed consent. The independent person kept the randomization list confidential until the end of the study.

Due to the nature of the intervention (oral carbohydrate drink versus traditional fasting), participants could not be blinded to their group allocation. The care providers and the principal investigator were also aware of the group assignments because they were responsible for administering the intervention and monitoring patients. However, the outcome assessor responsible for collecting postoperative pain scores (VAS), opioid consumption (MME), and functional assessments was blinded to group allocation. All outcome measurements were performed by a trained assessor who was unaware of whether the patient belonged to the ERAS or NPO group. Data analysis was performed on coded data without group identifiers, so the data analyst was also blinded to group allocation.

The deidentified individual participant data will not be shared because the study protocol and informed consent form do not include permission for public data sharing. Participant confidentiality is of utmost importance, and the data will be used solely for the purposes of this study.

Study protocol of the randomized controlled trial comparing Enhanced Recovery After Surgery with oral carbohydrate supplementation versus traditional nil per os fasting in patients undergoing total knee arthroplasty. The document includes the full study design, inclusion and exclusion criteria, intervention details, outcome definitions, sample size calculation, randomization method, and ethical considerations.

The study protocol will become available after publication of the main results of the trial, and will remain available for a period of 5 years from the date of publication.

The study protocol will be available to researchers working in academic institutions and non-commercial research organizations.

The study protocol may be used for non-commercial research purposes, including systematic reviews, meta-analyses, and replication studies. Requests will be reviewed by the principal investigator based on the scientific validity and ethical appropriateness of the proposed use.

Requests should be sent by email to the principal investigator: Nooshin Sarvi Sarmeydani Email: sarvi.n@ajums.ac.ir Affiliation: Department of Anesthesia, School of Paramedical Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Applicants should submit a written request by email stating their name, affiliation, purpose of use, and the intended analysis. The request will be reviewed by the principal investigator within 2 weeks. If approved, the study protocol will be sent electronically within 4 weeks of the request.