Ultrasound-guided adductor canal block for arthroscopic medial meniscectomy: A randomized, double-blind trial

Abstract

Purpose: The saphenous nerve block using a landmark-based approach has shown promise in reducing postoperative pain in patients undergoing arthroscopic medial meniscectomy. We hypothesized that performing an ultrasound-guided adductor canal saphenous block as part of a multimodal analgesic regimen would result in improved analgesia after arthroscopic medial meniscectomy. Methods: Fifty patients presenting for ambulatory arthroscopic medial meniscectomy under general anesthesia were prospectively randomized to receive an ultrasound-guided adductor canal block with 0.5% ropivacaine or a sham subcutaneous injection of sterile saline. Our primary outcome was resting pain scores (numerical rating scale; NRS) upon arrival to the postanesthesia care unit (PACU). Secondary outcomes included NRS at six hours, 12 hr, 18 hr, and 24 hr; postoperative nausea; and postoperative opioid consumption. Results: There was a statistically significant difference in mean NRS pain scores upon arrival to the PACU (P = 0.03): block group NRS = 1.71 (95% confidence interval [CI] 0.73 to 2.68) vs sham group NRS = 3.25 (95% CI 2.27 to 4.23). Cumulative opioid consumption (represented in oral morphine equivalents) over 24 hr was 71.8 mg (95% CI 56.5 to 87.2) in the sham group vs 44.9 mg (95% CI 29.5 to 60.2) in the block group (P = 0.016). Conclusions: An ultrasound-guided block at the adductor canal as part of a combined multimodal analgesic regimen significantly reduces resting pain scores in the PACU following arthroscopic medial meniscectomy. Furthermore, 24-hr postoperative opioid consumption and pain scores were also reduced. © 2013 Canadian Anesthesiologists' Society.