Femoral and popliteal aneurysms usually result from atherosclerosis and congenital weakness in the arterial wall. They also may result from trauma (blunt or penetrating), bacterial infection, or peripheral vascular reconstructive surgery (which causes “suture line” aneurysms or false aneurysms [also called pseudoaneurysm]).

With atherosclerotic changes, fatty, fibrous plaques narrow the lumen of the blood vessel. Narrowing of the lumen reduces the volume of blood flow, causing arterial insufficiency to the affected area.

This condition usually occurs in men older than age 50. The clinical course is usually progressive, eventually ending in thrombosis, embolization, and gangrene. Elective surgery before complications arise greatly improves the prognosis.

A popliteal aneurysm may cause pain in the popliteal space if it’s large enough to compress the medial popliteal nerve. It may cause edema and venous distention below the aneurysm if it compresses the vein. Femoral and popliteal aneurysms can produce symptoms of severe ischemia in the leg or foot from acute thrombosis in the aneurysmal sac, embolization of mural thrombus fragments and, rarely, rupture. Symptoms of acute aneurysmal thrombosis include severe pain, loss of pulse and color, coldness in the affected leg or foot, and gangrene. Distal petechial hemorrhages may develop from aneurysmal emboli.