his study will test whether giving dexamethasone through a vein can improve pain control after total hip replacement surgery. Dexamethasone is commonly used to reduce nausea and may also help with pain, but it is not clear which dose works best. Patients will be randomly assigned to receive either no dexamethasone, 4 mg, or 8 mg, in addition to standard anesthesia and a nerve block (PENG block). The main goal is to see how long patients go without needing additional pain medication after surgery. The study will also look at pain levels, use of opioid painkillers, nausea and vomiting, blood sugar levels, and possible side effects.

Effective pain control after total hip arthroplasty (THA) remains a key component of perioperative care, as inadequate analgesia may delay mobilization, prolong hospital stay, and increase the need for opioids. Regional anesthesia techniques, such as the pericapsular nerve group (PENG) block, are increasingly used to improve postoperative pain management while preserving motor function.

Dexamethasone administered intravenously is commonly used in perioperative care, primarily for the prevention of postoperative nausea and vomiting. In addition, it has been shown to prolong the duration of analgesia when used as an adjunct to regional anesthesia. However, there is still uncertainty regarding the optimal intravenous dose that provides clinically meaningful analgesic benefit without increasing the risk of adverse effects, particularly hyperglycemia.

Previous studies have typically used doses ranging from 4 mg to 8 mg, but direct comparisons between these doses, as well as comparison with placebo, remain limited in patients undergoing THA. Furthermore, the potential dose-response relationship of intravenous dexamethasone in this specific surgical population has not been clearly established.

This study is designed to address this knowledge gap by evaluating whether intravenous dexamethasone provides additional analgesic benefit in patients undergoing THA with PENG block, and whether higher doses result in improved outcomes compared to lower doses or no dexamethasone. The findings may help optimize perioperative analgesic strategies and support more evidence-based dosing of dexamethasone in orthopedic surgery.

Inclusion Criteria:

• Age ≥ 18 years
• Scheduled for elective total hip arthroplasty (THA)
• Planned use of regional anesthesia including PENG block
• American Society of Anesthesiologists (ASA) physical status I-III
• Ability to understand the study procedures and provide written informed consent
• Ability to assess pain using the Numeric Rating Scale (NRS)

Exclusion Criteria:

• Known hypersensitivity to dexamethasone or any component of the study medication
• Chronic corticosteroid therapy or use of systemic steroids within 14 days prior to surgery
• Active systemic infection or sepsis
• Significant immunosuppression (e.g., chemotherapy, biological therapy)
• Pregnancy or breastfeeding
• Severe cognitive impairment or inability to reliably assess pain
• Uncontrolled diabetes mellitus (e.g., HbA1c > 8.5% or baseline blood glucose > 200 mg/dL)