Popliteal artery entrapment syndrome (PAES) is an uncommon condition in which an abnormally positioned or enlarged calf muscle presses on the main artery behind the knee (popliteal artery). The artery becomes trapped, making it harder for blood to flow to the lower leg and foot.
Popliteal artery entrapment syndrome is most common among athletes.
The main symptom of popliteal artery entrapment syndrome (PAES) is pain or cramping in the back of the lower leg (the calf) that occurs during exercise and goes away with rest. Other signs and symptoms may include:
If the nearby vein (popliteal vein) also becomes trapped by the calf muscle, you may have:
Symptoms typically affect young, otherwise healthy people under age 40.
See your doctor if you have any type of leg pain, especially if you have calf or foot cramping during activity that gets better with rest.
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.
Popliteal artery entrapment syndrome (PAES) is uncommon. The following things increase your risk of the condition.
Long-term pressure on the popliteal artery can cause the artery to narrow (stenosis), causing pain and cramping with just slight activity, such as walking.
In severe cases or when undiagnosed, the nerves and muscles in the leg can become damaged. Blood clots may occur in the lower leg (deep vein thrombosis). Older athletes with signs and symptoms of popliteal artery entrapment syndrome should be checked for popliteal aneurysm, which is common in older men.
Your doctor will carefully examine you and ask questions about your symptoms and health history. However, because most people with popliteal artery entrapment syndrome (PAES) are young and usually healthy, diagnosing the condition can sometimes be challenging. The findings from a physical exam usually are normal.
Your doctor will rule out other causes of leg pain, including muscle strains, stress fractures, chronic exertional compartment syndrome and peripheral artery disease, which results from clogged arteries.
Tests used to rule out other conditions and diagnose PAES include the following:
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.
If you think you may have popliteal artery entrapment syndrome, it's important that you make an appointment with your doctor. If popliteal artery entrapment syndrome is found early, your treatment may be easier and more effective.
Because appointments can be brief, and because there's often a lot to discuss, it's a good idea to be prepared for your appointment. Here's some information to help you get ready for your appointment and know what to expect from your doctor.
Your time with your doctor is limited, so preparing a list of questions will help you make the most of your time together. List your questions from most important to least important, in case time runs out. For popliteal artery entrapment syndrome, some basic questions to ask your doctor include:
Don't hesitate to ask your doctor additional questions during your appointment.
Your doctor is likely to ask you a number of questions. Being ready to answer them may save time to go over any points you want to spend more time on. Your doctor may ask:
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