Comparison between Dexmedetomidine and Clonidine as an Adjuvant to Ropivacaine in Ultrasound-Guided Adductor Canal Block for Postoperative Analgesia in Total Knee Replacement: A Randomized Controlled Trial

BACKGROUND: Total knee replacement (TKR) surgeries are associated with significant postoperative pain. Ultrasound-guided adductor canal block is associated with better pain scores. The addition of Clonidine and Dexmedetomidine as additives to local anesthetics was the recent focus of interest. However, there are minimal studies comparing the duration of analgesia as additives to Ropivacaine in ultrasound-guided adductor canal block for TKRs. MATERIALS AND METHODS: Prospective, randomized, double-blind design was followed. One hundred and two American Society of Anesthesiologists I to III patients undergoing unilateral TKR surgeries were included in the study and randomized into two groups. Group C received Clonidine 150 mcg and Group D received Dexmedetomidine 100 mcg as an add on to 30 mL of 0.2% ropivacaine for adductor canal block. Postoperatively, duration of analgesia, sedation score, rescue analgesic requirement, hemodynamics, and any other adverse effects were monitored. RESULTS: The total duration of analgesia in Group D (16.01 h [standard deviation [S. D]-0.5]) was significantly higher as compared to Group C (13.02 h [S. D-0.5]) (P < 0.0001). The numerical rating score (NRS) was significantly lower in Group D compared to Group C (P < 0.05) at multiple postoperative timelines. Group D (2.25(S. D-0.44)) had better sedation scores as compared to Group C (2 [S. D-0]) (P = 0.001). CONCLUSION: Dexmedetomidine has longer duration, lower pain, and better sedation scores as compared to clonidine in adductor canal blocks for postoperative pain relief in TKR surgeries.