The preemptive analgesic effect of intraarticular bupivacaine and morphine after ambulatory arthroscopic knee surgery.

UNLABELLED: Intraarticular (IA) morphine provides effective postoperative analgesia after arthroscopic knee surgery. Some investigators have suggested that the preemptive administration of opioids may reduce postoperative analgesic requirements and hypersensitivity. We evaluated the analgesic effect of administering IA morphine either before or after surgical incision in patients undergoing arthroscopic knee surgery under local anesthesia. Forty patients undergoing arthroscopic meniscectomy were randomized into two groups. All patients received IA bupivacaine 0.25% before and after surgery together with IV sedation using midazolam and propofol. The Preemptive IA Morphine group received a single 3-mg dose of morphine with their preoperative bupivacaine. The Post-IA Morphine group received 3 mg of morphine at the completion of surgery with the postoperative bupivacaine. After surgery, pain scores, the time to first opioid use, and 24-h analgesic use were recorded. Analgesic duration, defined as the time from completion of surgery until first opioid use, was significantly longer in those patients receiving preoperative (953 +/- 209 min) versus postoperative (556 +/- 121 min) IA morphine. The 24-h acetaminophen and oxycodone use was less in the Preemptive group (2.2 +/- 1.2 pills) versus the Postoperative group (3.0 +/- 1.2 pills). We conclude that IA morphine provides a longer duration of postoperative analgesia with less 24-h opioid use when administered before surgery.

IMPLICATIONS: The administration of intraarticular morphine 3 mg before arthroscopic knee surgery provides a longer duration of analgesia with less 24-h opioid use compared with the administration of the drug at the completion of surgery.