Preemptive Femoral Nerve Block Could Reduce the Rebound Pain After Periarticular Injection in Total Knee Arthroplasty

BackgroundWe evaluated the effectiveness of postoperative pain management using intraoperative periarticular injection (PAI) and/or electromyography-guided preoperative femoral nerve block (FNB) in knees undergoing total knee arthroplasty (TKA).MethodsThis study included 90 patients (90 knees) who underwent primary TKA. Thirty patients received a single injection of electromyography-guided FNB, 30 received intraoperative PAI, and 30 received both. Pain at rest and while moving was evaluated by a visual analog scale (VAS) at 0, 4, 8, 24, and 48 hours. Postoperative range of motion, time to walking, amount of opioid consumption, and complications were analyzed.ResultsVAS immediately after surgery was significantly higher in the FNB group than in the PAI and combined groups, but did not differ significantly in the latter 2 groups. VAS after 4 and 8 hours showed similar results. VAS after 24 hours was significantly higher in the PAI than in the FNB and combined groups. After 48 hours, there were no differences among the 3 groups. Total opioid consumption was lower in the combined than in the FNB and PAI groups. Postoperative range of motion and time to walking were similar in the 3 groups.ConclusionPAI was more effective than FNB during the early (0-8 hours) postoperative period after TKA. Patients treated with PAI, however, experienced rebound pain at 24 hours. The combination of PAI and FNB may provide greater postoperative pain management than either alone for the first 24 hours after TKA.