Comparison of morphine and ropivacaine following knee arthroscopy

Purpose: The purpose of this study was to compare the effectiveness of ropi vacaine, a new local amidic anesthetic, compared with morphine as an intra- articular drug in controlling pain in patients after arthroscopic knee surg ery. Type of Study: Randomized trial. Methods: We enrolled 90 patients sche duled to undergo elective knee arthroscopy. Patients were homogenous regard ing demographic data and ASA physical status. Procedures included were diag nostic arthroscopies, lateral and medial meniscectomies, meniscal repair, a nd removal of loose bodies. All cases were treated by the same surgeon, und er general anesthesia, using the same procedure. Patients were randomly div ided into 3 groups. The first group received ropivacaine 75 mg in 20 mt of saline solution, the second group received 2 mg morphine in 20 mt of saline solution, and the third group received 20 mt of saline solution. No other oral or injectable analgesic administration was allowed. A blind observer a ssessed the patients' postoperative pain using a 10-cm visual analogue scal e (VAS), ranging from no pain (0) to unbearable pain (10). Scores were take n at 0, 1, 4, 6, 12, and 24 hours after drug injection. VAS scores were ana lyzed using analysis of variance; significance was set at P < .005. Results : None of the patients treated with ropivacaine or morphine needed administ ration of any other oral or injectable analgesic. No adverse reaction was n oted in ropivacaine group. VAS score analysis in the first 3 postoperative hours showed greater effectiveness for ropivacaine versus morphine or place bo with highly significant results (P < .001). In the first 24 postoperativ e hours, the ropivacaine group versus the morphine group showed no signific ant differences (P = .207). Conclusions: Although its cost is very high com pared with morphine, ropivacaine is a safe, site-specific, and long lasting anesthetic drug with an earlier onset than morphine and almost the same du ration, covering the whole postoperative period (24 hours).