A prospective, randomized controlled, double-blinded study comparing dexmedetomidine and clonidine as an adjuvant to ropivacaine in femoral nerve block for postoperative analgesia in patients undergoing total knee arthroplasty

Background Total knee arthroplasty (TKA) causes significant postoperative pain, imposing a limitation on postoperative mobilization crucial in regaining joint function. Ultrasound (US)-guided femoral nerve block (FNB) in complex knee surgeries is associated with better pain scores and fewer hospital admissions. Alpha-2 (alpha 2) adrenoreceptor agonists have been the recent focus of interest as additives to local anesthetic. We aimed to compare the equivalent dose of dexmedetomidine and clonidine as an adjuvant to ropivacaine in US-guided FNB in TKA. A prospective, randomized, controlled, double-blinded study was conducted involving 80 American Society of Anesthesiologists' physical status (ASA-PS) I, II, and III patients scheduled to undergo TKA under subarachnoid block. Group 1 (n = 40) patients received 1 mu g/kg dexmedetomidine and group 2 (n = 40) patients with 1 mu g/kg clonidine as adjuvants added to 20 ml of 0.75% ropivacaine. Duration of postoperative analgesia, pain scores, sedation scores, hemodynamics, rescue analgesia requirement, complications, and patient satisfaction were compared. Results The total duration of analgesia in group 1 was better compared to group 2 (p < 0.001). The patients were better sedated and the mean NRS scores were significantly lower (p < 0.05) in group 1 up to 24 h postoperatively. Total analgesic consumption was reduced in group 1, with a p value < 0.001. Patient satisfaction was significantly better (p < 0.001) in group 1 compared to group 2. Conclusion We conclude that dexmedetomidine added as an adjuvant in FNB increased the duration of analgesia when compared to clonidine with decreased NRS scores, reduced postoperative tramadol requirement, and better sedation and patient satisfaction.