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

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 20 ml 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 Conclusions Dexamethasone prolongs sensory block of single dose of femoral nerve block using ropivacaine. It also provides better analgesia and patient satisfaction, with fewer side effects.