Both lower extremities must be evaluated to determine the presence or extent of any disease and to ascertain the pulse status of the patient. The feet are examined for signs of peripheral vascular disease and the anterior and posterior tibial pulses are palpated. Because an intact arch can supply retrograde flow to the major vessels of the foot, it can be helpful to put pressure on the anterior tibial artery when detecting the presence of a posterior tibial pulse and visa-versa. This "modified Allen's test" may detect proximal vessel obstruction masked by an intact foot arch.
The need for preoperative angiography in young, healthy patients with a normal physical examination has been hotly debated. Our tendency has been to obtain preoperative angiograms as a guide. Although rare, we have seen lower extremities with a dominant peroneal artery nourishing the foot and distal anterior and posterior vessels, contraindicating sacrifice of the peroneal artery. MRI or CT angiography can also be used in many circumstances.