Low-dose intra-articular morphine injection for postoperative analgesia following knee arthroscopy

Objective To evaluate the effects of low-dose intra-articular morphine injection for postoperative analgesia after knee arthroscopy.Methods Sixty postoperative patients undergoing elective knee arthroscopy were randomized into two equal groups for intra-articular morphine injection at 2 mg solved in 5 ml saline solution(group A)or for injection with the same volume of normal saline(group B).At 2,4,8,16,24,48 and 72 h after the in- jections,the visual analogue scale(VAS)was measured for passive knee extension and 90-degree flexion,and the adverse effect in association with the injections were recorded.Results In group A,the VAS scores for passive knee extension at 4,8,16,24,48 and 72 h after the injection were significantly lower than those in group B(P0.05).The scores for knee flexion in group A at these time points were also significantly lower than those in group B(P0.05).The VAS scores at 2 h after injection were similar between the two groups.No serious adverse effects except for itching(in 1 case in each group)were observed in the two groups.Conclusion Low-dose intra-articular mor- phine injection can effectively relieve the pain after arthroscopic knee surgery.