A popliteal artery aneurysm is an irregular bulge that occurs in the wall of the artery located behind the knee joint. It is a type of lower extremity aneurysm.

You might not notice any symptoms. The first symptom may be pain in the lower leg that occurs with walking, called claudication. Other symptoms of a popliteal artery aneurysm include:

• Knee pain.
• Lower leg pain.
• Swelling behind the knee.
• Pulsing feeling behind the knee.

An aneurysm is a ballooning in a weak spot in an artery wall. Many different things can cause the popliteal artery wall to become weak, including:

• Atherosclerosis.
• High blood pressure.
• Wear and tear of the popliteal artery due to repeat use of the knee joint.

Popliteal artery aneurysms are rare. They are more common in men than in women.

Popliteal artery aneurysm often occurs in men with abdominal aortic aneurysm (AAA). An abdominal aortic aneurysm is a swelling of the wall of the body's main artery, called the aorta. Anyone diagnosed with popliteal artery aneurysm should be screened for AAA.

Other risk factors for popliteal artery aneurysm include:

• Growing older.
• High blood pressure.
• Smoking.
• Narrowing of a heart valve.
• Having three or more aneurysms anywhere in the body.

Complications of popliteal artery aneurysm include blood clots. Blood clots can cause a severe lack of blood flow in the lower leg.

A severe lack of blood flow can cause the following symptoms:

• A change in skin color in the affected area.
• No pulse behind the knee.
• Skin in the affected area feels cold.
• Numbness in the leg.
• Inability to move the foot.

A severe lack of blood flow may result in loss of the limb. Rarely, the aneurysm may rupture. But the risk of popliteal artery aneurysm rupture is low.

Smoking and high blood pressure increase the risk of blood vessel problems that can lead to popliteal artery and other aneurysms. Following a heart-healthy lifestyle can help prevent heart disease and blood vessel damage.

Try these heart-healthy tips:

• Do not smoke.
• Eat a nutritious diet.
• Get regular exercise.

To diagnose popliteal artery aneurysm, a health care professional usually does a physical exam and checks the legs for:

• Swelling.
• Tenderness.
• Changes in skin color or temperature on the lower leg and behind the knee.

You may be asked questions about your medical history and health habits, such as smoking.

Tests

Imaging tests can help confirm a diagnosis of popliteal artery aneurysm. Tests may include:

• Duplex ultrasound. This test uses sound waves to see how blood flows through the arteries and veins. It's a simple and quick way to diagnose popliteal artery aneurysm. For the test, a health care professional gently moves a hand-held ultrasound device on the skin behind and around the knee.
• CT angiography or magnetic resonance (MR) angiography. These tests take detailed images of blood flow in the arteries. Before the images are taken, dye called contrast is injected into a blood vessel. The dye helps the arteries show up more clearly.

Treatment of popliteal artery aneurysm depends on:

• The size of the aneurysm.
• The symptoms.
• Your age and overall health.

Treatment may include:

• Regular health checkups. You'll have frequent checkups and ultrasound tests to check the aneurysm, particularly if the aneurysm is small.
• Medicines. Aspirin or another blood thinner is usually prescribed for people with popliteal artery aneurysm. Medicines may need to be given through a vein. Blood pressure and cholesterol medicine may be given if you have symptoms of heart disease.
• Surgery. Open surgery to repair the damaged artery is generally recommended for any sized popliteal artery aneurysm that's causing symptoms. Surgery is usually done for any popliteal artery aneurysm that's 0.8 inches (2 centimeters) or larger. Sometimes, a less invasive procedure called endovascular repair may be done. During this treatment, a stent is placed inside the popliteal artery to hold it open.