A Comparison of Intraarticular Morphine and Bupivacaine for Pain Control After Outpatient Knee Arthroscopy

Abstract

To determine the duration of pain relief and efficacy of intraarticular morphine compared with bupivacaine after outpatient knee arthroscopy under local anesthe sia, we gave patients one of three postoperative intraar ticular injections: 4 mg morphine, 0.25% bupivacaine, or 0.9% saline. Visual analog scale scores and supple mental pain medication use were recorded at 0 to 30 minutes, 2, 4, 6, 8 to 12, and 24 hours after surgery. The score on the visual analog scale at 24 hours was sig nificantly lower in the morphine group than in the bupi vacaine or control groups. The cumulative amount of pain medication used was significantly lower in the mor phine and bupivacaine groups at 2 to 6 hours after sur gery than in the saline control group. The morphine group used the least supplemental pain medication dur ing the 12 to 24 hour interval ( P = 0.06). We found that the use of intraarticular morphine or bupivacaine after outpatient knee arthroscopy will de crease the amount of narcotic medication needed for pain relief during the early postoperative period. In ad dition, morphine provided prolonged pain relief up to 24 hours when compared with bupivacaine or placebo, and the patients in the morphine group tended to take less supplemental pain medication during the first postop erative day.