Medical Professional Publications

Femoral Nerve Block for Knee Surgery

(From the March 2014 Issue of PediatricsOnline)

Reducing postoperative pain, decreasing hospital admission, shortening length of stay upon admission and avoiding postoperative opioid use among children undergoing knee surgery may be as simple as performing a femoral nerve block, research shows. In a study of 376 pediatric knee surgeries at Nationwide Children’s Hospital, researchers found that the pain-prevention technique offers significant benefits over general anesthesia with surgical local anesthetic only.

A femoral nerve block (FNB) is a form of regional anesthesia that interrupts the signal of pain from the knee and thigh nerve to the brain, preventing the sensation of pain in that region of the body. Although it is not the most common regional anesthetic technique used in pediatric patients, femoral nerve block has been shown to reduce the need for hospital admission and opioid use in adult patients. To explore the procedure’s usefulness in pediatrics, physicians from the orthopaedic surgery program and the Department of Anesthesiology and Pain Medicine at Nationwide Children’s compared postoperative pain and other outcomes from patients receiving knee surgery with and without FNB at Nationwide Children’s outpatient surgery centers between 2008 and 2011.

FNB with general anesthesia was performed on 131 patients, and general and local anesthesia was given to 245 patients. While FNB did not reduce hospital admissions for all surgeries combined, researchers did discover a decrease in postoperative hospital admissions for pain management when FNB was used during surgery to repair an anterior cruciate ligament — commonly considered one of the most painful procedures. Only 71 percent of FNB patients receiving this type of surgery required admission to the hospital, compared to 95 percent of the non-FNB group.

Among all children admitted to the hospital postoperatively, FNB significantly shortened hospitalization, resulting in an average stay of 11.7 hours instead of 15.8. Postoperative pain scale scores were also significantly lower among FNB patients receiving all types of knee surgery. Those who received an FNB required intravenous opioids after surgery only 61 percent of the time, compared to 71 percent among non-FNB patients.

“This could potentially translate to a reduction of adverse outcomes and/or side effects related to narcotic consumption,” says Tarun Bhalla, MD, anesthesiologist at Nationwide Children’s and coauthor on the study, which appeared in the Journal of Pediatric Orthopedics in October. “In turn, that could decrease the cost of hospitalization and improve time to discharge, which is beneficial for the patient, the hospital and the insurance companies.”

Postoperative nausea and vomiting were not significantly different between groups in this study, although FNB has been found beneficial in reducing these common anesthesia-related side effects in other studies. To keep tabs on the impact of FNB, the anesthesia and pain management team actively participates in the Pediatric Regional Anesthesia Network database and continually examines outcomes for potential complications of nerve blocks they place during surgery.

“We now also place and track the results of femoral nerve catheters, which provide prolonged analgesia for two or three days postoperatively. We are finding that our FNB patients and families have an overwhelmingly positive experience, with minimal complications being reported,” says Dr. Bhalla. “Overall, our FNB work has improved patient outcomes and patient satisfaction scores. The orthopaedic surgeons are embracing this technique, which is optimizing the care we deliver to patients.”

The team’s results with supplemental FNB mirror those found in adult studies. Since the publication of their results, general anesthesia with FNB has become the standard of care for arthroscopic knee surgeries at Nationwide Children’s with continued success.

The team is now conducting a prospective, double-blind, randomized comparison of ultrasound-guided FNB to a lateral femoral cutaneous nerve block for pain control during and after traumatic femur fracture repair. “By providing a regional anesthetic technique, we are anticipating a reduction of narcotics necessary to keep the patient comfortable in the postoperative period as well a potentially shortened hospital stay,” says Dr. Bhalla, who also is the program director for the Pediatric Regional Anesthesia Fellowship.

Related Citation:
Schloss B, Bhalla T, Klingele K, Phillips D, Prestwich B, Tobias JD. A retrospective review of femoral nerve block for postoperative analgesia after knee surgery in the pediatric population. Journal of Pediatric Orthopedics. 2013 Oct 29. [Epub ahead of print]

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