Analgesic effects of intra-articular morphine during and after knee arthroscopy: a comparison of two methods

The objective of this study was to compare the analgesic effects of intra-articularly administered bupivacaine with bupivacaine/morphine during and after therapeutic knee arthroscopy. In a prospective, randomized study, 50 patients with clinical signs of medial meniscal injury were allocated to two groups, A and B. The patients in group A received 40 mL of 0.25% bupivacaine while the same dose of bupivacaine combined with 1 mg of morphine sulphate was administered in group B. Pain was estimated using the visual analogue scale (VAS) during surgery and at 2, 4, 6, and 24 hours after the operation was completed. Supplementary analgesic requirements were also registered, as well as the patients' overall rating of the entire procedure. The pain scores were significantly lower in Group B throughout the whole postoperative observation period. However, no significant differences were found between the two groups in terms of intraoperative pain scores, supplementary analgesic requirements, or the overall rating of the procedure. This study provides evidence that arthroscopic surgery can be performed in a safe manner after intra-articularly administered bupivacaine with or without low-dose morphine. The combination of low-dose morphine and bupivacaine did, however, produce a superior postoperative analgesic effect during the 24 hours following knee arthroscopy compared with bupivacaine alone.