This study is a prospective, non-randomized, case-control study. It was approved by the Institutional Review Board of Hanyang University Guri Hospital (HYGH 2013-P-14).

The subjects were 65-year-old or older hip fracture patients who visited the emergency department of a university hospital. The exclusion criteria were as follows: a relatively low pain score (numeric rating scale [NRS], less than 5 out of 10); the presence of accompanying injuries in other parts of the body in addition to a hip fracture; abnormal findings from a nerve/blood vessel examination of the lower limb affected by the hip fracture; difficulty in accurate physical examination or inquiry as a consequence of low consciousness levels or other reasons; and systolic blood pressure below 90 mmHg. We also excluded patients taking anticoagulants, those that had infections of the affected site, those allergic to local anesthetics, those expected to show a change in the anatomical structure of the affected site due to the surgery or procedure.

When an elderly patient aged over 65 years who was suspected of having a hip fracture arrived at the emergency department, inquiry and physical examination were performed initially, and then an intravenous line was established. Saline infusion was started at 100 mL/hr and 5 mg of morphine was administered through slow intravenous infusion for 2 minutes. A definite diagnosis of hip fracture was made using imaging, and if the patient did not meet any of the exclusion criteria, the researcher obtained informed consent for the research from the patient or the guardian and the procedure was performed. An emergency physician performed ultrasound guidance and needle manipulation with an emergency medicine resident’s assistance. None of the practitioners had any previous experience of regional anesthesia before taking part in the study; before participating in the study, they attended a one-hour lecture and practical training provided by a lecturer certified by World Interactive Network Focused on Critical Ultrasound (WINFOCUS). The regional anesthesia method used was three-in-one femoral nerve block [11]. The procedure was performed with monitoring of electrocardiography, blood pressure, and pulse oxygen saturation to anticipate emergency situations. The patient was placed in a supine position with the leg on the affected side in a state of external rotation. The pathways of the femoral vessels, iliacus muscle, and femoral nerve were determined in the emergency department by scanning the region just below the iliac ligament of the affected side using a high-frequency 12-MHz linear probe attached to an ultrasound testing machine (GE Logiq 7, GE Medical Systems, Milwaukee, WI, USA). Then, 20 mL of 0.5% bupivacaine was prepared in a 20 mL syringe as local anesthetic. The injection site was disinfected with chlorhexidine solution and the surrounding region was covered with a sterile cloth leaving only the injection site exposed. The ultrasound transducer was capped with a sterilized plastic cover to prevent infection. Under ultrasound guidance, the skin was punctured with a 21 G spinal needle approximately 2 cm lateral to the femoral artery and both fascia lata and fasica iliaca were penetrated in a succession until the tip of the needle was positioned close to the femoral nerve, after which the local anesthetic was injected around the femoral nerve (Fig. 1) After the injection, pressure was applied to a region approximately 2–4 cm below the puncture site for 5 minutes. We determined the outcome variable as the success of the regional anesthesia. The success of regional anesthesia was defined as the occurrence of dysesthesia in the anterior thigh. In addition, the pain score on a 10-point scale was measured just before regional anesthesia and 0.25, 0.5, 1, 2, 3, and 4 hours after the procedure. After regional anesthesia, the patient was checked for abnormal responses including low blood pressure, vascular perforation, needle damage to the bone, pain at the treated site, dizziness, tinnitus, perioral numbness, and absence of pain relief after 30 minutes. If additional analgesics were required, morphine was administered and the dose was recorded.

For patients that did not consent to regional anesthesia or could not undergo the procedure due to the absence of a practitioner, emergency department overcrowding, or any other reason, pain was controlled through intravenous morphine injection. Emergency physicians in charge of the patients in the morphine group were not aware of the study, and controlled pain according to the hospital’s established guidelines. These guidelines include intravenous infusion of 5 mg of morphine over 2 minutes followed by intravenous infusion of 2.5 mg at 10-minute intervals until the appearance of an appropriate analgesic effect. The presence of adverse reactions was checked before each injection and an additional dose was administered only when there was no adverse reaction. The total dose of morphine was decided at the emergency physician’s discretion. For the morphine group, the pain score was measured at 0.25, 0.5, 1, 2, 3, and 4 hours after the first morphine injection and the incidence of adverse reactions was recorded.

Statistical analyses were performed using SPSS ver. 18.0 for Mac (IBM Co., Armonk, NY, USA). For the descriptive statistics, nominal variables were expressed as frequency and percentage, ranking-scaled variables as median and quartiles, and ratio-scaled variables as mean and standard deviation. Fisher exact test was used to compare the frequency of adverse reactions between the regional anesthesia group and the morphine group, and t-tests were used to compare the pain scores.