Intra-articular morphine and bupivicaine for post-operative analgesia in anterior cruciate ligament reconstruction: a prospective randomised controlled trial

Anterior cruciate ligament reconstruction (ACLR) has the potential for significant post-operative pain. Conventional systemic opiate treatment may cause nausea and drowsiness, which may delay recovery. The use of intra-articular local anaesthesia has been shown to be effective. We wished to examine the additional effect of intra-articular morphine. This is a prospective, randomised, double-blind trial. Sixty patients were randomised to receive 20 ml 0.5% bupivicaine (group L, n = 30) or bupivicaine with 10 mg morphine (group M, n = 30) by intra-articular injection at the end of the operation. Visual analogue scores (VAS) were recorded before ACLR (expected pain) and repeated at 6 and 24 h after surgery. Time to first analgesic request and total systemic opiate and other analgesic use in the first 24 h was recorded. Pre-operative VAS measurements did not predict pain or analgesic use post-operatively. There were no significant differences between groups L and M with regard post-operative VAS or time to first analgesic request. Group M required less opiate analgesic post-operatively (oral morphine equivalent 50 mg for group L and 27 mg for group M, P < 0.007). There were no complications associated with the intra-articular analgesic. The simple addition of morphine to the intra-articular injection of bupivicaine gives a significant reduction in opiate analgesic requirement after ACLR.