Septic True Aneurysm of the Posterior Tibial Artery Diagnosed after Anterior Arthroscopic Debridement of a Septic Ankle following Infective Endocarditis: A Case Report

INTRODUCTION: There have been reports of true aneurysm of the posterior tibial artery, but only three reports have described true aneurysm of the posterior tibial artery at the ankle, and there has been only one report of tarsal tunnel syndrome caused by true aneurysm of this artery. In this case report, we describe a rare case of true septic aneurysm of the posterior tibial artery presenting as tarsal tunnel syndrome which was found after anterior arthroscopic debridement of a septic ankle in a 55-year-old man. CASE REPORT: 13 years earlier, this patient had undergone aortic valve replacement for severe aortic regurgitation caused by infective endocarditis with aortic valve vegetations. Since then, the patient had been treated with the oral anticoagulant warfarin. The aneurysm was successfully treated by a saphenous vein graft and administration of antibiotics. The patient likely developed septic ankle and aneurysm as a consequence of infective endocarditis. CONCLUSIONS: Magnetic resonance imaging should be performed before arthroscopic surgery to rule outaneurysm, especially in a patient with a septic ankle and/ora history of infective endocarditis.