BACKGROUNDTotal hip arthroplasty (THA) induces postoperative pain in elderly individuals. The erector spinae plane block (ESPB) is a novel analgesic approach for postoperative pain control. This randomized controlled trial evaluated the effectiveness of ultrasound-guided ESPB with ropivacaine in reducing pain in elderly patients undergoing THA METHODSPatients aged 60 to 80 years who had an American society of Aneshesiologists (ASA) physical status I to III were eligible for this study. There were 50 patients who were randomized into two groups: the ESPB group receiving ultrasound-guided ESPB with ropivacaine, and the control group receiving ESPB with normal saline. All patients underwent general anesthesia, and the mean arterial pressure (MAP), heart rate (HR), intraoperative opioid consumption, numerical rating scale (NRS) scores, and postoperative adverse reactions were recorded throughout the perioperative period. RESULTSA significant reduction in NRS scores was observed in the ESPB group compared to the control group at various time points, including in the recovery room and at 12 and 24 hours postoperatively (P < 0.05). When the observation period was extended to 48 hours, no significant difference in NRS scores was noted between the two groups (P > 0.05). No significant differences in MAP and HR were found between the two groups, but the ESPB group showed lower coefficients of variation (CV) for both MAP and HR. Moreover, the ESPB group demonstrated a significantly lower total remifentanil consumption than the control group. There was no significant difference in complications between these two groups (P < 0.05). CONCLUSIONSUltrasound-guided ESPB enhances the perioperative stability of mean arterial pressure and heart rate, providing effective analgesia within the initial 24 hours post-surgery, thereby reducing opioid requirements and improving overall postoperative recovery quality for elderly THA patients.