Abstract:Objective To evaluate the safety and efficacy of fascia iliaca compartment block（FICB）with liposomal bupivacaine in elderly frail surgical patients，and to investigate its influence of postoperative pain and delirium on patients. Methods Sixty patients undergoing total hip arthroplasty at Rugao People's Hospital from October 2023 to June 2025 were prospectively enrolled and randomly divided into two groups（n=30 per group）. Both groups underwent combined spinal-epidural anesthesia (CSEA). Before CSEA，the study group received ultrasound-guided FICB with 133 mg liposomal bupivacaine，while the control group received ultrasound-guided FICB with 30 mL of 0.25% bupivacaine.In both groups，dexmedetomidine was infused at 0.8 μg/kg for 10 min after nerve block，followed by continuous infusion at 0.4 μg·kg- 1·h- 1 until 10 min before the end of surgery. The following indicators were recorded and compared：Mini-Mental State Examination（MMSE）scores and tumor necrosis factor-α（TNF-α）level at preoperative day 1 and postoperative day 3；Visual Analogue Scale（VAS）scores at rest and during movement at 24 h and 48 h postoperatively；the number of analgesic pump compressions；the rate of rescue analgesia；the incidence of adverse reactions including delirium；and the time to first postoperative ambulation. Results On postoperative day 3，MMSE scores in both groups were lower than those on preoperative day 1，and the score in the study group was higher than that in the control group（P＜0.05）. On postoperative day 3，TNF-α levels in both groups were higher than those before surgery，and the level in the study group was lower than that in the control group（P＜0.05）. Compared with the control group，the study group had significantly lower VAS scores at rest and during movement at 24 h and 48 h postoperatively（P＜0.05），fewer analgesic pump compressions（1.87±0.43 vs 8.63±1.71，t=20.998，P＜0.05）and a lower rate of rescue analgesia（6.67% vs 30.00%，χ2=5.450，P＜0.05）. The incidence of delirium in the study group（6.67%）was slightly lower than that in the control group（20.00%），but the difference was not statistically significant（P=0.255）. The incidence of postoperative nausea and vomiting in the study group was significantly lower than that in the control group（P＜0.05）. There was no significant difference in the incidence of postoperative dizziness or time to first postoperative ambulation between the two groups（P＞0.05）. Conclusion Using bupivacaine liposome for FICB before CSEA，combined with dexmedetomidine，although it does not significantly reduce the incidence of delirium，it has more advantages in relieving postoperative pain，reducing inflammatory response and adverse reactions，and has high safety，which is suitable for elderly frail patients undergoing total hip arthroplasty.