A pilot randomised clinical trial of 3-in-1 femoral nerve block and intravenous morphine as primary analgesia for patients presenting to the emergency department with fractured hip

Abstract

Background: Fractured neck of femur (NOT) is a leading cause of morbidity and mortality in the elderly. Published clinical guidelines suggest early adequate analgesia as a key management aim. The femoral nerve '3-in-1 block' has previously been shown to provide effective analgesia for these patients in the peri- and post-operative phase of care. The aim of this study was to examine the use of the '3-in-1' femoral nerve block as primary analgesia for patients with a fractured NOT presenting to the emergency department. Methods: This was a single centre pragmatic randomised controlled open-label trial comparing femoral nerve block (using a '3-in-1' technique) with intravenous (IV) morphine. A convenience sample of patients presenting to the emergency department of a district general hospital with a clinically or radiologically suspected fractured NOT were recruited. They were randomised to receive either 0.1 mg/kg IV bolus of morphine or a '3-in-1' femoral nerve block with 30 mi of 0.5% plain bupivacaine. Visual analogue pain scores were noted prior to treatment and at 30 minutes, 2 hours, 6 hours and 12 hours after treatment. Immediate complications such as vascular puncture or the requirement for naloxone were noted. Results: Forty patients were recruited, 22 patients were randomised to IV morphine and 18 patients were randomised to '3-in-1' femoral nerve block. Complete data were available for 33 patients. There was no significant difference in initial median pain score (p=0.45). Analysis using the Wilcoxon test showed a significant decrease in pain score for the morphine group (p=0.01) and the nerve block group (p<0.01) at 30 minutes compared with baseline. Analysis using the Mann-Whitney U test between median pain scores at each time point showed a significant lower pain score in the nerve block group at 30 minutes (p=0.046). There were no immediate complications in either group. Conclusion: Our results suggest that a '3-in-1' femoral nerve block is at least as effective as IV morphine when used as primary analgesia for patients with fractured NOF Our results suggest that the femoral nerve block may provide better analgesia at 30 minutes. Further larger scale randomised trials are warranted.