Popliteal artery entrapment syndrome (PAES) is a rare condition that occurs when the popliteal artery, which supplies blood to the lower leg and foot, is compressed or pinched by surrounding muscles or other tissues in the popliteal fossa behind the knee. This can result in reduced blood flow to the lower leg and foot and can cause pain, cramping, or numbness in the affected leg during physical activity.

PAES is more common in young adults, particularly those who are physically active and involved in sports. It can be caused by an abnormal anatomy of the popliteal artery or surrounding muscles, or by repetitive or strenuous physical activity that puts pressure on the artery.

Symptoms of PAES may include pain or cramping in the calf or foot during physical activity, numbness or tingling in the foot, muscle weakness, or a cold or pale foot. These symptoms may improve with rest.

Diagnosis of PAES typically involves a physical exam, imaging tests such as ultrasound or MRI, and sometimes angiography to evaluate the extent of the artery compression.

Treatment for PAES usually involves surgery to release the compression of the popliteal artery. This can involve cutting or removing the muscles or tissues that are compressing the artery, or repairing any abnormalities in the artery or surrounding tissues.

If PAES is suspected, it is important to seek medical attention promptly to prevent potential complications, such as blood clot formation or tissue damage, which can be serious or life-threatening.

Popliteal artery entrapment syndrome (PAES) is caused by an abnormal calf muscle, usually the gastrocnemius muscle.

The condition may occur from birth (congenital) or develop later in life (acquired). In the congenital form, the calf muscle or nearby artery is abnormally positioned while the baby grows in the mother's womb. People with the acquired form of PAES have a calf muscle that is bigger than normal (enlarged).

The abnormal calf muscle presses on the main artery behind the knee (popliteal artery), reducing blood flow to the lower leg. The lack of blood flow results in pain and cramping in the back of the lower leg during times of activity.

Surgery is the only way to correct the abnormal calf muscle and free the trapped artery. Your doctor will likely recommend surgery if your symptoms significantly affect your everyday or athletic activities.

During surgery, the surgeon makes an incision on the inner calf just below the knee, or in the back of the knee, to release the abnormal calf muscle and give the artery more room. This will prevent the calf muscle from pressing on the artery in the future. Surgery is done while you are under general anesthesia. The procedure takes about an hour. Typically, you'll need to stay in the hospital for one day.

If you've had the condition for a long time, you may need artery bypass surgery. Bypass surgery is usually done only on those who have severe narrowing of the artery (stenosis) due to long-term popliteal artery entrapment syndrome.

Surgery to release the calf muscle and artery usually doesn't affect leg function. When the condition is diagnosed and treated early, a full recovery is expected, and your symptoms should disappear.