A Longitudinal Supra-Inguinal Fascia Iliaca Compartment Block Reduces Morphine Consumption After Total Hip Arthroplasty

Abstract

Background and objectives: The role of a fascia iliaca compartment block (FICB) for postoperative analgesia after total hip arthroplasty (THA) remains questionable. High-dose local anesthetics and a proximal injection site may be essential for successful analgesia. High-dose local anesthetics may pose a risk for local anesthetic systemic toxicity. We hypothesized that a high-dose longitudinal supra-inguinal FICB is safe and decreases postoperative morphine consumption after anterior approach THA.

Methods: We conducted a prospective, double blind, randomized controlled trial. Patients scheduled for THA were randomized to group FICB (longitudinal supra-inguinal FICB with 40-mL ropivacaine 0.5%) or group C (control, no block). Standard hypothesis tests (t test or Mann-Whitney U test, χ test) were performed to analyze baseline characteristics and outcome parameters. The primary end point of the study was total morphine (mg) consumption at 24 hours postoperatively. Serial total and free ropivacaine serum levels were determined in 10 patients.

Results: After obtaining ethical committee approval and written informed consent, 88 patients were included. Mean (SD) morphine consumption at 24 hours postoperatively was reduced in group FICB compared to group C: 10.25 (1.64) mg versus 19.0 (2.4) mg (P = 0.004). Using a mean dose of 2.6-mg/kg ropivacaine (range, 2-3.4 mg/kg), none of the patients had total or free ropivacaine levels above the maximum tolerated serum concentration.

Conclusions: We conclude that a high-dose longitudinal supra-inguinal FICB reduces postoperative morphine requirements after anterior approach THA.Clinical Trials Registry: EU Clinical Trials Register. www.clinicaltrialsregister.eu #2014-002122-12.