Our aim will be to investigate the efficacy of dexmedetomidine as an adjuvant to bupivacaine in ultrasound guided pericapsular nerve group (PENG) block for postoperative analgesia in hip replacement surgeries.

• Our primary outcome of the study: total amount of postoperative morphine consumption in the first 24h postoperative.
• Our secondary outcome of the study: postoperative analgesia assessed by pain score (by Visual Analog Scale)

Effective postoperative pain management is essential for optimizing recovery and patient outcomes following hip surgeries.

The pericapsular nerve group (PENG) block has gained attention as a regional anesthesia technique that provides targeted analgesia to the hip joint and surrounding structures, reducing opioid consumption and avoiding its side effects as nausea, vomiting, constipation, itching, rash, addiction, urinary retention, respiratory depression especially at higher doses By delivering local anesthetics close to the genicular branches of the femoral nerve, the pericapsular nerve group (PENG) block offers several advantages as part of multimodal analgesia in comparison to other nerve blocks used for hip surgeries, such as the femoral nerve block (FNB) and the lumbar plexus block (LPB) as better pain relief for capsular structures with minimal motor blockade, lower risk of complications and reducing need for opioids making it particularly suitable for orthopedic procedures.

Traditionally, local anesthetics such as bupivacaine have been used in the pericapsular nerve group (PENG) block to achieve effective analgesia. However, despite its long acting properties, their duration of action is typically limited to 6 to 12 hours depending on factors like the concentration, dose and individual patient characteristics and the quality of analgesia may diminish as the anesthetic effect wears off, potentially necessitating additional analgesic interventions or systemic opioids to maintain pain control.

Therefore, there is a growing interest in exploring adjuvants that can enhance the efficacy and duration of pain relief without compromising safety such as Dexmedetomidine, Clonidine, and Dexamethasone.

Dexmedetomidine, a highly selective alpha-2 adrenergic agonist, has emerged as a promising adjuvant in prolonging the duration and improving the quality of peripheral nerve blocks through its potent analgesic and sedative effects, by binding to its receptors, reducing the release of norepinephrine and inhibiting pain transmission , by this mechanism not only enhances sensory blockade but also provides effective postoperative analgesia with minimal motor impairment.

Studies have shown that dexmedetomidine, when added to local anesthetics in various regional anesthesia techniques, including peripheral nerve blocks, significantly prolongs the duration of sensory blockade and improves postoperative pain scores.

Given the potential benefits of dexmedetomidine in enhancing postoperative pain management and reducing opioid requirements, this study aims to evaluate its efficacy as an adjuvant to bupivacaine in the pericapsular nerve group (PENG) block for hip replacement surgeries. By assessing, opioid consumption and pain scores, this research seeks to contribute valuable insights into optimizing analgesic strategies in orthopedic anesthesia.

Inclusion Criteria:

• Patients aged from 18 years to 90 years
• Gender : both males and females
• BMI less than 35 kg/m2
• Patients with American society of anesthesiologists (ASA) classification class I , II or III
• Patients scheduled for total or partial hip replacement surgery under spinal anesthesia

Exclusion Criteria:

• Patient declining to give written informed consent
• Patient with infection at the site of injection
• Patient with coagulopathy
• Patients with known allergy to used medications.
• Psychiatric disorder