Postoperative analgesia with '3-in-1' femoral nerve block after prosthetic hip surgery

Abstract

To evaluate the efficacy of a single shot '3-in-1' femoral nerve block for prosthetic hip surgery in association with general anaesthesia on post-operative analgesia. Methods: Forty patients, ASA 1 to 3, received sham block or '3-in-1' femoral nerve block, following Winnies landmarks with a nerve stimulator, and 40 ml bupivacaine 0.5% with epinephrine were injected after induction of anaesthesia. Vecuronium, 0.1 mg · kg-1, was added after performing the block and anaesthesia was maintained with isoflurane, oxygen 40% and nitrous oxide 60%. Fentanyl, 1.5 μg · kg-1, was administered before incision to all patients. Heart rate, blood pressure, fentanyl requirements and F(ET)iso were measured throughout surgery. During the post-operative period, 75 mg diclofenac im and/or 0.1 mg · kg-1 morphine sc were administered when pain score was > 3/10 and repeated when necessary. Pain scores at first analgesic intervention, at 24 hr and 48 hr as well as diclofenac and morphine requirements after surgery were recorded. Results: There was no difference in anaesthetic requirements during surgery. The time from performance of sham or '3-in-1' femoral nerve block to the first analgesic intervention (261 ± 49 min versus 492 ± 40 min, P < 0.05) and time from extubation to the first analgesic intervention (61 ± 44 min vs 298 ± 39 min, P < 0.05) were prolonged in the study group. However, pain scores and the analgesic requirements in the postoperative periods (24 and 48 hr) were similar. Conclusion: There is a short-term benefit during the first few postoperative hours in using a single shot '3-in-1' femoral nerve block to complement general anaesthesia for elective hip surgery.