Acute Limb Ischemia Caused by Distal Embolization from an External Iliac Artery Pseudoaneurysm Associated with a Protruding Acetabular Screw: A Case Report

This case report describes a 78-year-old female who presented with acute limb ischemia caused by distal embolization 23 years after total hip arthroplasty (THA). The embolic source was a pseudoaneurysm of the left external iliac artery (EIA) densely adherent to thickened soft tissue in contact with a protruding acetabular screw. The affected EIA segment was replaced with a prosthetic graft, and an above-knee popliteal-to-posterior tibial artery bypass was performed for infrapopliteal occlusion. Histopathology revealed disruption of the elastic laminae, replacement of the arterial wall by granulation tissue with prominent hemosiderin deposition, and organizing thrombus, confined to the side facing the screw, whereas the opposite wall was preserved. Vascular complications of THA are uncommon and usually occur perioperatively; however, chronic mechanical irritation from a protruding acetabular screw may contribute to delayed pseudoaneurysm formation and distal embolization. The patient remained free of recurrent pseudoaneurysm, embolization, and graft stenosis throughout 10 years of follow-up.