A retrospective review of femoral nerve block for postoperative analgesia after knee surgery in the pediatric population

Abstract

Background: To investigate the outcomes of pediatric patients receiving a femoral nerve block (FNB) in addition to general anesthesia for arthroscopic knee surgery compared with those receiving general anesthesia alone.

Methods: This retrospective review included all patients undergoing arthroscopic knee surgery from January 2009 to January 2011 under general anesthesia both with and without a FNB. After the induction of general anesthesia, those patients selected for regional anesthesia received a FNB using real-time ultrasound or nerve stimulator guidance. For the FNB, 0.2 to 0.4 mL/kg of local anesthetic solution was injected around the femoral nerve at the level of the inguinal crease. Intra-articular injection of bupivacaine (0.25%, 10 mL) was administered by the surgeon for all patients not receiving a FNB. Additional analgesic medications, PACU length of stay, duration of hospitalization, hospital course, and any acute or nonacute complications were recorded and evaluated.

Results: There were no adverse effects related to the FNB. Using a 0 to 10 visual analogue scale (0=no pain), there was a statistically significant difference in both the high (4.0 ± 4.0 vs. 5.3 ± 3.1, P=0.0004) and low (1.5 ± 1.8 vs. 2.1 ± 2.0, P=0.002) pain scores in patients who received a FNB versus those who did not with the scores being lower in those who had received a FNB. There was a decreased need for the use of opioids postoperatively (61% vs. 71%, P=0.04) and a decreased duration of postoperative stay in patients who were admitted to the hospital (11.7 ± 8.1 vs. 15.8 ± 10 h, P=0.044) in individuals who had a FNB. There was a significantly lower admission rate in patients undergoing anterior cruciate ligament repair in the FNB group (72% vs. 95%, P=0.001). There was no difference in the incidence of postoperative nausea and vomiting between the groups.

Conclusion: After arthroscopic knee surgery in pediatric patients, a FNB shortens hospital stay, reduces opioid requirements, and decreases postoperative pain scores. For anterior cruciate ligament repairs, FNB lowers postoperative admission rates.

Clinical evidence: Level III.