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

PURPOSE 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 Winnie's 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 microgram.kg-1, was administered before incision to all patients. Heart rate, blood pressure, fentanyl requirements and FETiso were measured throughout surgery. During the post-operative period, 75 mg diclofenac i.m. and/or 0.1 mg.kg-1 morphine s.c. 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.