Comparison of Bupivacaine and Ropivacaine for Postoperative Analgesia in Ultrasound-Guided Femoro-Sciatic Nerve Block in Patients Undergoing Below Knee Surgery: A Randomized Controlled Trial

Below knee surgeries require effective postoperative pain management to optimize patient outcomes and facilitate early mobilization. This randomized, double-blind, controlled trial aimed to compare the efficacy of bupivacaine versus ropivacaine for postoperative analgesia in ultrasound-guided femoro-sciatic nerve block in patients undergoing below knee surgery. A total of 120 patients aged 18-70 years, ASA physical status I-III, scheduled for elective below knee surgeries were randomly allocated into two groups of 60 patients each: Group B received 0.5% bupivacaine 30 mL and Group R received 0.5% ropivacaine 30 mL for combined femoral and sciatic nerve blocks under ultrasound guidance. The primary outcome was duration of postoperative analgesia, defined as time to first rescue analgesic request. Secondary outcomes included onset time, block characteristics, pain scores using visual analog scale, total analgesic consumption, patient satisfaction, and adverse effects. The duration of postoperative analgesia was significantly longer in Group B compared to Group R (18.4 ± 3.2 hours vs 14.7 ± 2.8 hours, p<0.001). Onset of sensory block was faster with ropivacaine (12.8 ± 3.4 minutes vs 15.6 ± 4.1 minutes, p<0.01), while motor block onset was comparable between groups. Pain scores were significantly lower in Group B at 12 and 18 hours postoperatively. Total morphine consumption over 24 hours was lower in Group B (8.6 ± 3.2 mg vs 12.4 ± 4.1 mg, p<0.001). Patient satisfaction scores were higher in the bupivacaine group. No significant complications or adverse effects were observed in either group. Both bupivacaine and ropivacaine provide effective postoperative analgesia for below knee surgeries when used in ultrasound-guided femoro-sciatic nerve blocks. Bupivacaine demonstrated superior duration of analgesia and reduced analgesic requirements, while ropivacaine offered faster onset and excellent safety profile. The choice between these agents should be individualized based on surgical requirements, patient factors, and desired duration of analgesia.