Early CTA Diagnosis of Hemodynamically Occult External Iliac Artery Injury After Direct Anterior Total Hip Arthroplasty Treated with Covered Stent–Graft Repair: A Case Report

Introduction: Major retroperitoneal arterial bleeding may remain clinically difficult to recognize when vital signs are initially stable. Case presentation: We report the case of a 67-year-old man who developed progressive abdominal and right groin pain radiating to the ipsilateral flank, accompanied by two episodes of vomiting and an early hemoglobin (Hb) and hematocrit decline on the first postoperative day after right-sided direct anterior total hip arthroplasty (THA). Despite the absence of hemodynamic instability, computed tomography angiography (CTA) demonstrated active contrast extravasation from the right external iliac artery (EIA) with a large retroperitoneal hematoma. CTA localized the bleeding source and enabled immediate endovascular treatment planning. Subsequent angiography confirmed active extravasation from the right EIA, and a covered stent–graft was deployed through ultrasound-guided superficial femoral artery access, achieving complete exclusion of the bleeding source with preserved arterial patency. The subsequent Hb nadir and transfusion were interpreted as reflecting preceding retroperitoneal blood loss rather than persistent bleeding, because follow-up CTA showed a stable hematoma without active extravasation. The patient was discharged in stable condition, and 1-month duplex ultrasound and following 3-month CTA confirmed stent–graft patency. Discussion: This case highlights the diagnostic mismatch that may occur between substantial retroperitoneal blood loss and initially reassuring hemodynamic findings. When progressive abdominal or groin symptoms are accompanied by a serial, otherwise unexplained Hb decline, CTA may be more informative than DUS for suspected deep pelvic bleeding because it can identify active extravasation, define hematoma extent, assess alternative abdominopelvic causes, and support treatment planning. In anatomically suitable lesions, covered stent–graft repair can rapidly control hemorrhage while preserving EIA patency. Conclusions: Stable vital signs do not exclude major retroperitoneal arterial bleeding after direct anterior THA. Progressive abdominal or groin pain with early postoperative Hb decline should raise suspicion for occult vascular injury, for which CTA can provide rapid diagnosis and guide immediate endovascular management.