Blood flow to each leg is supplied through the femoral artery in the thigh, which continues into the popliteal artery behind the knee.  The popliteal artery divides into three tibial arteries, which supply blood flow to the lower leg and foot.  All of these arteries are common sites for the build-up of plaque and the development of arterial blockage (stenosis), which can lead to severe loss of circulation to the feet.  If the condition goes untreated, the feet will become cold, painful and discolored, and may develop open sores or even gangrene.  These problems can affect any patient with hardening of the arteries, but they are especially common in patients with diabetes.  

Vascular surgeons are able to restore blood flow to the legs by performing arterial bypass procedures.  A femoral-tibial bypass is performed by implanting a small tube to carry blood flow from the femoral artery in the groin directly to the one of the tibial arteries, bypassing the blocked sections of the leg arteries.  Ideally this bypass tube ("graft") will be made from the patient's own leg veins, usually the saphenous vein, which is part of a network of veins located in the fatty tissue under the skin.  Occasionally the surgeon will need to borrow veins from the other leg, or even the arms.  Although special plastic tubes are sometimes used for other kinds of bypass surgery, they do not work well for femoral-tibial bypass.

In addition to the bypass procedure itself, patients with open sores or gangrene of the foot sometimes require surgical removal of the unhealthy tissue in order to obtain complete healing.

Femoral-tibial bypass is a major surgical procedure requiring several days in the hospital and several weeks of recovery.  If performed by well-trained and properly qualifed vascular surgeons, it has a high success rate in relieving the symptoms of poor circulation and saving legs that might otherwise require amputation.