Although intra-operative local infiltration analgesia has gained increasing popularity in joint replacement surgery, it is not clear whether postoperative local infusion analgesia using an indwelling catheter provides clinically important additional effects. We, therefore, conducted a randomized controlled trial to clarify the efficacy of the originally developed local infusion analgesia technique in total knee arthroplasty.
Forty patients were randomly allocated to the local infusion analgesia or control group. Patients in the local infusion analgesia group received intermittent bolus intra-articular injection of analgesics consisting of ropivacaine, dexamethasone, and isepamicin until postoperative 48 h. Primary outcome was pain severity at rest using 100-mm visual analogue scale.
Pain severity in patients of the local infusion analgesia group was lower than control group, and there were significant differences between groups at POD1 (p = 0.025) and POD3 (p = 0.007). Reduction of postoperative pain was associated with a decrease in C-reactive protein level and earlier achievement of straight leg raise. In addition, postoperative drain volume was reduced in the local infusion analgesia group.
Although larger studies are needed to examine its safety, the local infusion analgesia alone provided clinically significant analgesic effects and rapid recovery in total knee arthroplasty.