Effect of intra-articular dexmedetomidine on postoperative analgesia after arthroscopic knee surgery

Abstract

Background: Alpha-2-adrenergic agonists have peripheral analgesic effects. We have assessed the potential analgesic effect of dexmedetomidine after intra-articular administration in arthroscopic knee surgery. Methods: Sixty patients undergoing arthroscopic knee surgery were randomly assigned into three groups in a double-blind placebo controlled study. The control group received i.v. and intra-articular saline, the intra-articular group received i.v. saline and intra-articular dexmedetomidine, and the i.v. group received i.v. dexmedetomidine and intra-articular saline. Haemodynamic changes, pain visual analogue scale (VAS), sedation score, the time to first postoperative analgesic request, and the total postoperative analgesic use during the first 24 h were evaluated. Results: Dexmedetomidine administration resulted in a significant reduction in pain scores for 6 h after operation in the intra-articular group but only for 1 h in the i.v. group. The time to first postoperative analgesic request was longer in the intra-articular group [312.0 (sd 120.7) min] compared with the control group [71.0 (50.1) min] and the i.v. group [102.1 (54.4) min] (P<0.001). Total diclofenac requirement was significantly lower in the intra-articular group [90.0 (46.2) mg] than in the control group [165.0 (52.2) mg] and in the i.v. group [129.3 (54.3) mg] (P<0.05). Conclusions: Intra-articular dexmedetomidine enhanced postoperative analgesia after arthroscopic knee surgery, with an increased time to first analgesic request and a decreased need for postoperative analgesia. © The Board of Management and Trustees of the British Journal of Anaesthesia 2008. All rights reserved.