Effect of Preemptive Femoral Nerve Block on Pain Control and Opioid Consumption After Total Knee Arthroplasty: A Randomized Controlled Trial

Aim: Peripheral nerve blocks, particularly femoral nerve blocks (FNBs), are a practical choice for relieving severe pain after total knee arthroplasty (TKA). We investigated the effectiveness of preemptive FNB on postoperative pain control and the reduction of opioid consumption. Methods: This was a single-center, prospective, randomized controlled trial conducted at a tertiary care health center, Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Turkey. The study included 40 American Society of Anesthesiologists I-III patients scheduled for elective TKA surgery. Patients were studied in two groups. The FNB group (n=20) received preemptive single-injection FNB (15 mL of prilocaine 2% and 15 mL of 0.5% bupivacaine using a peripheral nerve stimulator) before general anesthesia (GA) as the study group and the control group (n=20) received standardized GA. The primary outcome measure was pain scores evaluated as numeric pain rating scale (0-10) at 2, 4, 8, 12, 16, 18, 20, and 24 h. Secondary outcome measures included opioid consumption with patient-controlled and perioperative hemodynamic changes. Results: Pain scores and opioid consumption in the FNB group were significantly lower than those in the control group at every measurement time (p