Addition of femoral 3-in-1 blockade to intra-articular ropivacaine 0.2% does not reduce analgesic requirements following arthroscopic knee surgery

Abstract

Purpose: To test the hypothesis that the addition of a preincisional femoral 3-in-1 block to intra-articular instillation with ropivacaine 0.2% at the end of surgery improves postoperative pain control in patients undergoing arthroscopic anterior cruciate ligament reconstruction (ACLR) under general anesthesia. Methods: In a prospective, randomized, placebo-controlled, double-blind trial, we studied 44 patients scheduled for inpatient ACLR. Prior to incision, the treatment group (n = 22) received a femoral 3-in-1 block with 40 ml ropivacaine 0.2%, augmented by infiltrations of the lateral and anteromedial incisions with 20 ml ropivacaine 0.2% at the end of the procedure. The control group (n = 22) received saline 0.9% instead of ropivacaine. All patients received an intra-articular instillation with 30 ml ropivacaine 0.2% at the end of surgery. The primary efficacy variable was 24 hr morphine consumption postoperatively standardized by weight, administered intravenously via a patient-controlled analgesia (PCA) pump. Results: There was no difference between both groups in 24 hr PCA morphine consumption postoperatively (control, 0.45 ± 0.44 [mean ± SD] mg · kg-1; treatment, 0.37 ± 0.50 mg · kg-1; P = 0.55). No difference was found in postoperative visual analog scale pain scores, adverse events, or vital signs. In the treatment group, R = 10/22 patients did not require postoperative morphine compared with R = 6/22 in the control group (P = 0.35). Conclusion: We found no effect of a femoral 3-in-1 block with ropivacaine 0.2%. on postoperative analgesic consumption, compared to intra- articular instillation with ropivacaine 0.2% alone, in patients undergoing ACLR under general anesthesia.