Background: Small or systematically inactive doses of morphine administered into the knee joint during intra-articular surgery can elicit potent and long-lasting postoperative analgesia. The reports studied in USA, Spain, UK, Germany, Ireland, etc. showed that intra-articular morphine 0.5-5 mg could produce a significant analgesic effect with an onset time of 0-6 h after administration and a duration of 24-48 h. However, there were no available data about the Chinese people; therefore, this study was designed to collect the data regarding this subject.
Methods: Forty patients undergoing arthroscopic knee surgery under spinal anesthesia were randomly divided into two groups. At the end of surgery, group 1 received intra-articular morphine sulfate 1 mg in normal saline 10 ml, while group 2 received intra-articular 0.5% bupivacaine 10 ml for postoperative pain relief.
Results: The results showed that all pain scores were lower in morphine group than in bupivacaine group from 6 to 24 h after surgery. Supplemental analgesic consumption was significantly greater in the bupivacaine group than in the morphine group from 6 to 24 h postoperatively. These results were quite similar with those presented in other races.
Conclusions: We concluded that intra-articular morphine 1 mg in Chinese patients could provide an effective and long-lasting analgesic effect, which was quite similar with the result presented in other races.