Dexmedetomidine and clonidine as adjuvants to ropivacaine in adductor canal block for postoperative analgesia in patients undergoing arthroscopic anterior cruciate ligament reconstruction: A prospective, randomized, double-blind study

Abstract

Background: Patients undergoing arthroscopic anterior cruciate ligament (ACL) reconstruction experience significant postoperative pain, which could lead to a delay in recovery and discharge from an ambulatory surgical setting. Adductor canal block (ACB) has been used to offer effective postoperative analgesia after ACL repair. We compared the analgesic efficacy of alpha-2 agonists clonidine and dexmedetomidine as adjuvants to local anesthetics in ACB. Patients and Methods: Sixty subjects scheduled for elective arthroscopic ACL reconstruction were randomized into two groups of 30 patients each. Group 1 patients received US-guided ACB with 20 mL of 0.5% ropivacaine with 1 μg/kg clonidine as an adjuvant; group 2 patients received ACB with 20 mL of 0.5% ropivacaine with 1 μg/kg dexmedetomidine as an adjuvant. Demographic data, pain scores, motor and sensory block, postoperative tramadol consumption, time to rescue analgesia, and adverse events were compared. Results: The demographic data were comparable between both groups. The patients in group 2 when compared with group 1 had increased time for request to rescue analgesic (488.83 ± 67.934 min compared with 975.07 ± 90.251 min, P < 0.001), reduced tramadol consumption (179.33 ± 44.095 mg compared with 179.33 ± 44.095 mg, P < 0.001), and better pain scores at 12 and 18 h. Postoperative nausea and vomiting was less in group 2 compared with group 1. Conclusion: Dexmedetomidine, when added as an adjuvant to 0.5% ropivacaine in ACB, leads to increased time to first request of tramadol, reduced postoperative tramadol requirement, and decreased NRS scores when compared with clonidine.