Comparing two medicine for pain relief after lower limb surgery aiming to find which one provides better and longer lasting pain relief with fewer side effects

INTERVENTION: Intervention1: Group BF: Group BF will receive 15 ml of Bupivacaine and 50 mcg of Fentanyl and pain will be assessed by VAS score Control Intervention1: Group BN: Group BN will receive 15 ml of bupivacaine and 10 mg of Nalbuphine and pain will be assessed with VAS score CONDITION: Health Condition 1: 4‐ Measurement and Monitoring PRIMARY OUTCOME: 1.Postoperative analgesia by Visual Analog scale ; 2.To measure the need for rescue analgesia ; Timepoint: 1.Postoperative analgesia by Visual Analog scale ; 2.To measure the need for rescue analgesia ; SECONDARY OUTCOME: 1. Hemodynamic parameters including HR, MAP. ; 2. Postoperative complication related to Fentanyl & Nalbuphine ; 3. Level of sedation using Ramsay Sedation Score ; 4. Patient satisfaction using Likert scale.Timepoint: Baseline ,Every 5 minutes till 40 minutes then every 10 minutes till 90 minutes INCLUSION CRITERIA: Patients aged 25 to 60 years. Gender both males and females ASA grade 1 and 2 Scheduled for elective lower limb orthopedic surgeries Patient providing written informed consent