Continuous Femoral Nerve Block Provides Superior Analgesia Compared With Continuous Intra-articular and Wound Infusion After Anterior Cruciate Ligament Reconstruction

Abstract

This prospective, randomized, clinical trial compared pain intensity and analgesic drug consumption after anterior cruciate ligament (ACL) reconstruction with patellar tendon under femoral-sciatic nerve block anesthesia in patients who received either a continuous femoral nerve block (CFNB) or continuous local anesthetic wound and intra-articular infusions. Fifty patients were randomized to CFNB (n = 25) or an ON-Q device (I-Flow Corp, Lake Forest, Calif) (n = 25). All patients received sciatic nerve block (25 mL of ropivacaine 7.5 mg/mL and clonidine 30 microg). The first group received a CFNB (2 mg/mL of ropivacaine at 7 mL/hr), and the second group received a single-shot femoral nerve block (both using 25 mL of ropivacaine 7.5 mg/mL and clonidine 30 microg). At the end of the intervention, an ON-Q device was positioned on the ON-Q patients to continuously infuse the patellar tendon wound and intra-articular cavity with ropivacaine 2 mg/mL at 2 mL/hr for each catheter. Data regarding demographic, hemodynamic, pain scores, adverse effects, and need for supplemental analgesia were registered in a 36-hr follow-up period. The CFNB group reported lower visual analog scale values than the ON-Q group: at rest at 12 hrs (2.4 [SD, 2.2] vs 5.4 [SD, 3.1]; P < 0.001) and on movement at 12 (3.1 [SD, 2.5] vs 6.3 [SD, 2.9]; P < 0.001) and 24 hrs (2.7 [SD, 1.9] vs 4.6 [SD, 2.6]; P = 0.01) after surgery. The number of morphine and ketorolac boluses was lower in the CNFB group (morphine: 3.2 [SD, 2.2] vs 6.2 [SD, 2.5]; P < 0.001; ketorolac: 1.1 [SD, 1.0] vs 2.4 [SD, 0.9]; P < 0.001). Continuous femoral nerve block provides better analgesia than the continuous patellar tendon wound and intra-articular infusions after anterior cruciate ligament reconstruction with patellar tendon.