Comparison Between Fentanyl and Dexmedetomidine As Adjuvant to Bupivacaine in Combined IPACK and Adductor Canal Block for Postoperative Analgesia After Knee Surgeries

• To measure the total amount of rescue analgesic consumption in the first 48 hours post-operatively in each group
• To assess pain score in each group by using Numerical Rating Scale (NRS) at rest (static) and during flexion or extension of knee (dynamic) at different time points: PACU, 2 hrs, 4 hrs, 8 hrs, 12 hrs, 24 hrs and 48 hrs.
• To measure the time of first request of rescue analgesia in each group
• To record the incidence of adverse events (hematoma, local anesthetic toxicity, infection, nausea and vomiting) and length of hospital stay.
• Over all patients' satisfaction: The patients will be asked to rate the overall degree of satisfaction of the analgesia by using a 5-points Likert-like verbal scale (1 = very dissatisfied analgesia, 2 = dissatisfied analgesia, and 3 = neutral, 4=satisfied analgesia, and 5=very satisfied analgesia).

Inclusion criteria

1 - Patient acceptance 2. Cooperative patients 3. Age: ≥21 and 85< years' old 4. Sex: both sexes (males or females). 5. Physical status: ASA Ι & II& Ш. 6. Body Mass Index (BMI): ≤ 35 kg/m2. 7. Type of operation: elective unilateral knee surgeries (TKA, ACL, knee arthroscopy)

Exclusion criteria

. Patient with any contraindications of regional blocks (as coagulopathy or local infection at injection site) 2. Patients with known history of allergy to the study drugs (bupivacaine, dexmedetomidine and fentanyl).

• Advanced hepatic, renal, cardiovascular, neurologic and respiratory diseases.

4.Chronic opioid use (more than 3 months or daily oral morphine > 5 mg /day for 1 month)

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