Abstract: BACKGROUND: Hip fracture is a common and serious injury in the elderly population, with postoperative pain management directly impacting rehabilitation quality and functional recovery. While peripheral nerve blocks have become an integral component of multimodal analgesia, systematic comparison of different blocking techniques across various types of hip fractures remains limited.
OBJECTIVE: To compare the analgesic effects, safety profiles, and postoperative recovery impacts of fascia iliaca compartment block and femoral nerve block in different types of hip fracture surgeries. 
METHODS: A total of 180 patients scheduled for hip fracture surgery between January 2022 and June 2024 were enrolled and divided according to fracture type into femoral neck fracture group (n=60), intertrochanteric fracture group (n=60), and subtrochanteric fracture group (n=60). Patients in each group were randomly assigned to either fascia iliaca compartment block group or femoral nerve block group using a random number table, with 30 patients in each subgroup. Corresponding nerve blocks were performed preoperatively. Numerical Rating Scale scores at immediate postoperative, 6, 12, and 24 hours postoperatively, morphine consumption within 24 hours, time to first ambulation, length of hospital stay, inflammatory markers (interleukin-6, tumor necrosis factor-α) and stress response indicators (cortisol, blood glucose) at 24 hours postoperatively, and incidence of adverse reactions were recorded. Multivariate regression analysis was performed to identify factors influencing analgesic efficacy, and a nomogram prediction model was constructed.
RESULTS AND CONCLUSION: (1) In femoral neck fracture and intertrochanteric fracture subgroups, fascia iliaca compartment block group showed significantly lower Numerical Rating Scale scores than femoral nerve block group at immediate postoperative, 6 and 12 hours (P < 0.01). (2) In femoral neck fracture group, the mean differences were 0.86 points (95%CI: 0.47-1.25), 0.90 points (95%CI: 0.45-1.35), and 0.79 points (95%CI: 0.30-1.28), respectively; in intertrochanteric fracture group, the mean differences were 0.83 points (95%CI: 0.43-1.23), 0.87 points (95%CI: 0.44-1.30), and 0.70 points (95%CI: 0.31-1.09), respectively. (3) In femoral neck fracture and intertrochanteric fracture groups, morphine consumption within 24 hours was significantly reduced (all P < 0.001), time to first ambulation was earlier (all P < 0.05), and length of hospital stay was shorter (all P < 0.05) in the fascia iliaca compartment block subgroup compared with the femoral nerve block subgroup. (4) In subtrochanteric fracture group, no significant differences were observed between fascia iliaca compartment block and femoral nerve block subgroups in all observed parameters (P > 0.05). (5) Fascia iliaca compartment block group showed significantly lower levels of inflammatory markers interleukin-6 (P < 0.001), tumor necrosis factor-α (P < 0.001) and stress indicators cortisol (P < 0.001), blood glucose 
(P < 0.001) compared with femoral nerve block group. The overall incidence of adverse reactions was comparable between the two blocking techniques (P=0.825), mainly including nausea/vomiting, constipation, and urinary retention. (6) Multivariate regression analysis revealed that block technique (β=-3.76, P < 0.001), fracture type (subtrochanteric fracture β=5.47, P < 0.001), age ≥75 years (β=-1.75, P=0.022), and American Society of Anesthesiologists grade III (β=2.32, P=0.016) were independent predictors of analgesic efficacy. (7) The nomogram prediction model demonstrated good calibration. Interleukin-6 levels were positively correlated with length of hospital stay (r=0.42, P < 0.001) and time to first ambulation (r=0.38, P < 0.001). It is concluded that compared with femoral nerve block, fascia iliaca compartment block provides superior postoperative analgesia for patients with femoral neck fractures and intertrochanteric fractures, significantly reduces inflammatory and stress responses, shortens time to first ambulation and hospital stay, and promotes early recovery. However, in patients with subtrochanteric fractures, the two blocking techniques show comparable efficacy. Block technique, fracture type, age, and American Society of Anesthesiologists grade are independent factors influencing analgesic efficacy. The constructed nomogram prediction model can provide reference for individualized analgesic strategy selection in clinical practice.

Key words: fascia iliaca compartment block, femoral nerve block, hip fracture, femoral neck fracture, intertrochanteric fracture, subtrochanteric fracture, postoperative analgesia