Analgesic effect of a single-dose of perineural dexamethasone on ultrasound-guided femoral nerve block after total knee replacement

Abstract

Introduction: Total knee replacement is usually a very painful procedure. A single-dose of femoral nerve block has been shown to provide similar analgesia to an epidural, with fewer side effects, but limited in time.Objective: To compare the analgesia provided by dexamethasone used at perineural level in the femoral nerve block after total knee replacement with the one used at intravenous level, and with that of a control group.Material and methods: A prospective, randomised, double-blind controlled trial was conducted on 81 patients randomly assigned to one of three groups: 1) IV dexamethasone (8 mg); 2) perineural dexamethasone (8 mg), and 3) placebo. All patients received 20ml of ropivacaine 0.5% for femoral nerve block. The primary outcome was the duration of the sensory-analgesic block of the femoral nerve block. The secondary outcomes included pain intensity measurements, patient satisfaction, and incidence of complications.Results: Randomisation was effective. Analgesia duration was significantly higher (P