Spinal anaesthesia with adjunctive intrathecal morphine versus continuous lumbar plexus blockade: a randomised comparison for analgesia after hip replacement

Following elective total hip replacement, both continuous lumbar plexus blockade and spinal anaesthesia (with adjunctive intrathecal morphine) have shown early outcome benefits over opioid analgesia and single-injection nerve block. However, the two techniques have not been compared in a prospective randomised manner. Our study examined 50 patients undergoing elective hip joint replacement who were randomised to receive spinal anaesthesia (with adjunctive intrathecal morphine 0.1 mg) or patient-controlled continuous lumbar plexus blockade. All surgery was conducted under general anaesthesia. Measured outcomes included numerically rated postoperative pain, supplemental opioid consumption and indices of mobilisation together with complications. Results show that block placement time was marginally shorter for the spinal group (5 versus 7 minutes, P=0.01). The primary outcome, worst pain on movement/mobilisation during the first 24 hours, was not statistically significantly different between groups. Patients in the lumbar plexus group were given more intraoperative opioid and rescue morphine in the post-anaesthesia care unit (median = 4 versus 0 mg, P