Intra-articular morphine versus bupivacaine for postoperative pain management.

The purpose of this study was to determine whether morphine would be as effective as bupivacaine for postoperative pain control after knee arthroscopy with no worsening of the side effect profile. Eighty-two patients who underwent partial meniscectomy, chondral debridement, or both were prospectively randomized to receive 10 mg of morphine (10-cc volume) or 10 cc of .5% bupivacaine immediately postoperatively. Visual analog scale scores and side effect profiles were recorded in the postanesthesia care unit, in the transitional care unit, and then every 4 hours postoperatively until 24 hours. In-hospital data were available for all 82 patients, but postdischarge data were available for only 64 patients. Visual analog scale scores in the postanesthesia care unit decreased from 3.4 on admission to 2.4 on discharge for the morphine group and from 2.6 to 2.4 for the bupivacaine group (P>.217, all time points). Medication use was the same for both groups in the hospital (62% and 78%, respectively) with no statistical difference. Visual analog scale scores decreased from 3.0 to 1.5 for the morphine group and from 2.8 to 1.8 for the bupivacaine group between 4 and 24 hours postoperatively (P>.376, all time points). Medication use decreased between 4 and 24 hours postoperatively for both groups, from 71.7% to 52.9%, respectively, with no statistical difference at all time points. Four patients in the morphine group and 1 patient in the bupivacaine group experienced side effects. This study indicates that 10 mg of intra-articular morphine is as effective as 10 cc of .5% bupivacaine for postoperative pain control for partial meniscectomy and chondral debridement of the knee. It minimally increases side effects initially and circumvents the issue of chondral toxicity of bupivacaine.