Efficacy of intra-articular cocktail analgesic injection in total knee arthroplasty - a randomized controlled trial.

In a randomized, double-blind, placebo, parallel and controlled study, 80 patients with osteoarthritis who underwent unilateral TKA were randomly assigned to two groups: Trial Group, where patients received intra-articular intraoperative injection containing morphine, bupivacaine and betamethasone, and Control Group, where patients received normal saline as control. All patients received patient-controlled analgesia (PCA) for 48 h postoperatively. We found that intra-articular cocktail analgesic injection significantly reduced the morphine consumption during the 0-36 h postoperative period and the total morphine consumption. VAS at rest in Trial Group at postoperative 6, 10, 24 and 36 h was significantly lower than that in Control Group, and VAS during activity in Trial Group at postoperative 24 h and 36 h was significantly lower than that in Control Group. The time of ability to perform an active straight leg raise and to actively reach 90 degrees knee flexion, as well as ROM of the knee at the 15th postoperative day, was better in Trial Group than those in Control Group. There were no significant differences in postoperative wound healing, infection, blood pressure, heart rate, rash, respiratory depression, urine retention and DVT between the two groups. The occurrence of nausea and vomiting in Trial Group was lower than that of Control Group. This study revealed that intra-articular cocktail analgesic injection reduced the need for morphine and offered a better pain control, without apparent risks following TKA.