Intra-articular morphine for pain relief after anterior cruciate ligament repair.

We have performed a randomized, double-blind controlled study in patients undergoing elective anterior cruciate ligament repair, to assess the effect of intra-articular morphine on postoperative pain. The morphine group (n = 11) received morphine 5 mg in saline 25 ml and the control group (n = 9), saline 25 ml intra-articularly. Patients in the morphine group had significantly smaller pain scores throughout the 24-h postoperative period compared with those in the control group (P < 0.05). There was less requirement for supplementary analgesics in the morphine group.