The goal of this clinical trial is to evaluate whether an opioid-sparing postoperative pain regimen can reduce opioid consumption and maintain effective pain control in adults undergoing anterior total hip arthroplasty for osteoarthritis.

The main questions it aims to answer are:

• Does an opioid-limited regimen result in lower postoperative opioid use compared with a standard opioid prescription?
• Does the opioid-limited regimen provide comparable or improved postoperative pain control and patient satisfaction?

This study evaluates whether an opioid-sparing postoperative regimen can reduce opioid use while maintaining effective pain control in adults undergoing anterior total hip arthroplasty for osteoarthritis. Although opioids are commonly used after joint replacement, they carry risks such as side effects and long-term dependence. Multimodal analgesic strategies-using combinations of non-opioid medications and local anesthetic techniques-have shown promise in reducing opioid requirements while providing adequate pain relief.

All participants in this randomized, double-blind trial will receive a standardized multimodal non-opioid pain regimen throughout the perioperative period, along with counseling from a Life Care Specialist. Participants will be assigned to receive either a standard opioid prescription or placebo tablets at discharge, with a small supply of rescue hydromorphone available for severe breakthrough pain. Pain scores, nausea, opioid consumption, and patient-reported outcomes will be collected during the first postoperative week and at follow-up visits at 3 weeks and 3 months. The study aims to determine whether limiting routine opioid prescribing after hip arthroplasty can safely reduce opioid exposure without compromising recovery or patient satisfaction.

Inclusion Criteria:

• Diagnosis of hip osteoarthritis requiring primary arthroplasty
• Scheduled to undergo anterior total hip arthroplasty (THA)
• Able to comply with study procedures and follow-up visits
• Able to provide informed consent

Exclusion Criteria:

• Concurrent significant injuries to other bones or organs
• Local infection at or near the surgical site
• Preoperative opioid use within 4 weeks prior to surgery
• History of severe heart disease (NYHA Class II or higher), renal failure, or liver dysfunction
• Chronic liver disease
• Neurological or psychiatric conditions that may influence pain perception
• Pregnancy
• History of alcohol or medication abuse
• Inability to take NSAIDs
• Use of postoperative DVT prophylaxis other than aspirin 81 mg twice daily
• Diabetes mellitus with HbA1c > 8.0%
• Diagnosis of chronic pain syndrome or fibromyalgia
• Pain Catastrophizing Scale (PCS) score > 29
• Any condition that, in the investigator's judgment, may interfere with adherence to study procedures or follow-up

De-identified individual participant data underlying the primary and secondary outcomes of the study, including:

Daily postoperative pain scores (Numeric Rating Scale, POD 1-7) Opioid consumption data (oral morphine equivalents) at 7 days, 3 weeks, and 3 months Patient-reported outcome measures (HOOS Jr., EQ-5D, Subjective Hip Value) Patient-reported satisfaction with pain control Medication-related side effects (e.g., nausea, constipation) Opioid refill information Length of stay, emergency department visits, readmissions, and reoperations

Data will become available after publication of the primary study results and will remain available for up to 5 years following publication, contingent upon institutional data retention policies.

De-identified data will be shared with qualified researchers whose proposed use of the data has been approved by the study investigators.

Requests for data access must be submitted to the corresponding author. Approved requests will be granted through a secure data-sharing mechanism (e.g., encrypted file transfer or institutional data-sharing platform) following execution of a data use agreement, as required.