Epidural morphine after anterior cruciate ligament repair: a comparison with patient-controlled intravenous morphine

To compare the management of postoperative pain using morphine administered by epidural catheter with intravenous patient-controlled analgesia (PCA), we prospectively studied 47 consecutive cases involving repair of the anterior cruciate ligament of the knee. Both the quality of analgesia and the incidence of side effects were documented. Compared with patients receiving PCA morphine, patients given epidural morphine reported significantly lower pain scores both at rest (0.7 +/- 1.1 versus 3.4 +/- 2.1, P less than 0.01) and with mobilization (3.2 +/- 2.1 versus 6.1 +/- 2.1, P less than 0.01). Although patients receiving epidural morphine had a greater incidence of urinary retention, there were no significant differences in the incidence of nausea or pruritus. There was no respiratory depression in either group. We conclude that epidural morphine provides superior analgesia with a clinically inconsequential increase in side effects. Further, epidural morphine may have special advantages when early mobilization is indicated.