Comparing the Efficacy of Intra-Articular Application of Morphine and Tramadol on Postoperative Pain After Arthroscopic Knee Surgery

BACKGROUND Intra-articular analgesia is a pain reliever that is frequently administered following arthroscopic knee surgery. OBJECTIVES The purpose of this study was to compare the efficacy of intra-articular application of morphine and tramadol on postoperative pain after arthroscopic knee surgery. PATIENTS AND METHODS For this randomized double blinded clinical trial, 132 patients undergoing minor arthroscopic knee surgery were randomly assigned to receive either; 5 mg morphine or 50 mg tramadol intra-articularly. Pain was evaluated by means of the verbal pain rating score (VRS) preoperatively (at rest and on movement of the knee joint) and postoperatively at 0, 1, 2, 3, 4, 6, 12 and 24 hours. Meanwhile, the time of the first analgesic request and need for supplemental analgesic were also recorded. RESULTS There was no statistically significant difference in VRS scoring between the two groups during the preoperative period either at rest or on knee movement. Meanwhile, VRS scores did not differ significantly between the morphine and tramadol treated groups postoperatively, except for in the one-hour post-operative scores in which the tramadol-treated group experienced less pain (P < 0.007). Post-operative VRS scores at 6, 12, and 24 hours were significantly decreased when compared with previous scores in both morphine and tramadol prescribed subjects (P < 0.001), hence, both local analgesics can significantly reduce pain after minor knee surgery. CONCLUSIONS We have found a postoperative analgesic effect of intra-articularly administered morphine and tramadol following minor arthroscopic knee surgeries with a maximum effect 6 hours post injection.