The Effect of Intraarticular Injection of Morphine and Bupivacaine on Postarthroscopic Pain Control

This study sought to compare the effects of morphine, bupivacaine, and saline injected into the knee after ar throscopic surgery. In a double-blind, randomized trial, 124 patients received either bupivacaine, morphine, bupivacaine and morphine, or saline at the completion of surgery. Postoperative pain was assessed with a 100-mm visual analog pain scale. Analgesic require ments were calculated, and weightbearing status was recorded. We found that morphine alone injected in traarticularly at the completion of arthroscopic knee sur gery had no significant effect on postoperative pain, need for supplemental analgesia, or weightbearing sta tus. Patients receiving morphine in combination with bupivacaine did not demonstrate any statistically sig nificant improvement over those receiving bupivacaine alone. Therefore, our results failed to show any ben eficial effect of morphine used for postoperative anal gesia, either alone or in combination with bupivacaine. The overall pattern in all patients demonstrated de creased pain scores, decreased analgesic use, and in creased weightbearing status as the observation period progressed. Finally, preoperative pain was correlated with pain at discharge, indicating that the most signifi cant predictor of postoperative pain was preoperative level of discomfort.