Arteriovenous malformation mimicking femoral osteolysis after total hip arthroplasty.

We encountered a case of apparent progressive femoral osteolysis around a well-fixed cementless implant in a young patient. At the time of revision arthroplasty, massive hemorrhaging occurred during exposure and attempted femoral component extraction. Urgent packing of the exposed endosteum with polymethyl methacrylate controlled the bone bleeding. Emergent angiography confirmed an arteriovenous malformation with extensive proximal diaphyseal involvement directly at the site of osteolysis. This arteriovenous malformation was treated successfully with selective arterial embolization and second-stage resection. In retrospect, the index arthroplasty operative note indicated an excessive amount of blood loss, and prerevision radiographs showed osteolysis with uncharacteristic vascular markings. The presence of an osteolytic lesion in total hip arthroplasty should not be assumed to be attributed to polyethylene granuloma, and any atypical radiographic features should prompt further preoperative investigations.