Ultrasound-guided adductor canal block after arthroscopic anterior cruciate ligament reconstruction: Effect of adding dexamethasone to bupivacaine, a randomized controlled trial

Background Dexamethasone improves the quality and duration of peripheral nerve block when used as an adjuvant to local anaesthetic. We evaluated the effect of adding dexamethasone to bupivacaine on the duration of postoperative analgesia in patients undergoing knee arthroscopy using ultrasound-guided adductor canal block. Methods The study was a randomized, double-blinded trial. Sixty patients scheduled for arthroscopic anterior cruciate ligament reconstruction were randomly allocated into two groups to receive adductor canal block. The control group received 20 mL bupivacaine 0.5% + 2 mL normal saline, and the dexamethasone group received 20 mL bupivacaine 0.5% + 2 mL dexamethasone (8 mg). Measurements included onset and duration of sensory blockade, visual analog score, time to first analgesic requirement, analgesic consumption, satisfaction score and assessment of quadriceps strength. Results Duration of sensory block was significantly longer in the dexamethasone group (17.42 +/- 5.24 h) than the control group (12.52 +/- 1.16 h), p < 0.001. The visual analog score was significantly lower (p < 0.05) in the dexamethasone group. Time to first analgesic requirement was significantly longer in the dexamethasone group (13.37 +/- 3.68 h) compared with the control group (10.57 +/- 0.93 h), p < 0.001. Ketorolac dose as a rescue analgesic was significantly higher in the control group (p < 0.001), whereas patients' satisfaction score was significantly higher in the dexamethasone group (p < 0.001). Conclusion The addition of dexamethasone to bupivacaine in adductor canal block provides prolonged postoperative analgesia and less postoperative analgesic consumption than bupivacaine alone in anterior cruciate ligament arthroscopic surgery. Significance Adding dexamethasone to bupivacaine in adductor canal block significantly increases the duration of sensory block, time to first analgesic requirement and patients' satisfaction score in anterior cruciate ligament arthroscopic surgery.