Xing JG, Abdallah FW, Brull R, Oldfield S, Dold A, Murnaghan ML, Whelan DB. Preoperative femoral nerve block for hip arthroscopy: a randomized, triple-masked controlled trial. Am J Sports Med. 2015;43(11):2680-7.
In adults having hip arthroscopy, what is the analgesic effect of preoperative femoral nerve block (FNB)?
Randomized (allocation concealed), blinded (patients, clinicians performing the block, intraoperative anesthesiologists, surgeons and surgical staff, data collectors, and nurses), controlled trial with 7 days of follow-up.
Women’s College Hospital in Toronto, Ontario, Canada.
52 patients 18 to 65 years of age (mean age, 32 years; 70% men) had hip arthroscopy by 1 of 2 fellowship-trained orthopaedic surgeons, spoke English as a first language, had American Society of Anesthesiologists classifications I to III, and had a body mass index of <38 kg/m2. 96% of patients completed follow-up.
Ultrasound-guided preoperative FNB with use of 20 mL of 0.5% ropivacaine with 1:400,000 epinephrine (n = 27) or 20 mL of normal saline solution (n = 23). Block was administered outside of the operating room by a regional staff anesthesiologist, anesthesia fellow, or directly supervised resident. All patients received midazolam and fentanyl for sedation. After infiltration with 1% lidocaine, block solution was administered under ultrasound guidance to achieve a circumferential spread around the femoral nerve. Block effectiveness was assessed at 5, 10, and 15 minutes. All patients received acetaminophen (1 g) and celecoxib (400 mg) 1 hour before surgery and received standardized intraoperative anesthesia and postoperative analgesia including oral celecoxib (200 mg, twice a day for 3 weeks) and oral oxycodone (5 mg, every 4 hours as needed).
Main outcome measures:
The primary outcome was cumulative postoperative opioid consumption (oral morphine-equivalent) at 24 hours after surgery. Secondary outcomes included opioid consumption at 48 hours and 7 days, pain severity scores, and complications.
The study had 90% power to detect a 30% reduction in opioid consumption between groups. The FNB group had lower opioid consumption at 48 hours but not at 24 hours or 7 days (Table). Pain scores were lower in the FNB group at 30 minutes and at 1, 2, 4, and 6 hours but not at 24 or 48 hours or at 7 days. The groups did not differ in terms of nausea and vomiting, constipation, itching, pain at the injection site, or bruising. 6 patients (22%) in the FNB group had noninjurious falls within 24 hours after surgery, compared with 0 patients in the saline solution group (p = 0.025).
In patients having hip arthroscopy, preoperative FNB did not reduce opioid consumption at 24 hours but reduced postoperative pain compared with normal saline solution. FNB increased noninjurious falls within 24 hours after surgery and therefore is not recommended for routine use in hip arthroscopy.
Source of funding:
For correspondence: Dr. J.G. Xing, Division of Orthopaedic Surgery, University of Toronto, Toronto, Ontario, Canada. E-mail address: email@example.com
FNB has been extensively studied as an adjunct to general anesthesia for total knee replacement and anterior cruciate ligament reconstructive surgery. Although there are perioperative benefits, complications, including femoral nerve palsy, quadriceps weakness, falls, and even fractures, have been reported1,2. Regional nerve blocks also have been studied in the setting of hip arthroscopy3. Although FNB has small beneficial effects, including improved pain scores, reduced opioid consumption, and reduced postoperative nausea, the risks are still too great4. The well-designed trial by Xing and colleagues shows that despite these perioperative benefits, patients who received FNB had an increased risk of falls. Appropriate pain control is crucial for all orthopaedic procedures, but the catastrophic side effects of falls, fractures, and femoral nerve palsy outweigh the benefits. Therefore, I applaud and concur with the authors’ conclusion and believe that FNB should not be the standard of care for patients undergoing hip arthroscopy.
Disclosure: The author indicated that no external funding was received for any aspect of this work. On the Disclosure of Potential Conflicts of Interest forms, which are provided with the online version of the article, the author checked “yes” to indicate that he had a relevant financial relationship in the biomedical arena outside the submitted work.
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