The preemptive analgesic effect of intraarticular bupivacaine and morphineafter ambulatory arthroscopic knee surgery

Intraarticular (IA) morphine provides effective postoperative analgesia aft er arthroscopic knee surgery. Some investigators have suggested that the pr eemptive administration of opioids may reduce postoperative analgesic requi rements and hypersensitivity. We evaluated the analgesic effect of administ ering IA morphine either before or after surgical incision in patients unde rgoing arthroscopic knee surgery under local anesthesia. Forty patients und ergoing arthroscopic meniscectomy were randomized into two groups. All pati ents received IA bupivacaine 0.25% before and after surgery together with I V sedation using midazolam and propofol. The Preemptive IA Morphine group r eceived 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 (95 3 +/- 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.