Popliteal Artery Entrapment – Symptoms and Causes

Overview

Popliteal artery entrapment syndrome (PAES) is a rare condition affecting the main artery behind the knee.

This syndrome occurs when the popliteal artery becomes compressed by an abnormally positioned or enlarged calf muscle, restricting blood flow to the lower leg and foot.

Athletes face a higher risk of developing this condition compared to the general population. When the calf muscle compresses the artery, it creates a blockage that limits blood circulation during physical activity, potentially causing pain and other symptoms.

The compression happens because of either:

• Abnormal muscle position
• Enlarged calf muscle

Blood flow restriction may worsen during exercise when muscles contract and expand.

Signs and Symptoms

Pain or cramping in the back of the lower leg (calf) is the main symptom of popliteal artery entrapment syndrome. This pain happens during exercise and stops when you rest.

People with this condition may also experience:

• Cold feet after physical activity
• Tingling or burning sensations in the calf
• Numbness in the calf area

When the popliteal vein gets trapped by the calf muscle, additional symptoms might include:

• Feeling of heaviness in the leg
• Night-time calf cramping
• Swelling around the calf
• Changes in skin color near the calf muscle
• Deep vein thrombosis (blood clot in the lower leg)

Most people affected by this condition are young and healthy individuals under 40 years old.

When To Consult a Healthcare Provider

If you experience any type of leg pain, schedule a medical appointment. This is particularly important when you have calf or foot cramping during activities that improve with rest.

Early diagnosis can help prevent complications and ensure appropriate treatment.

Causes

Popliteal artery entrapment syndrome (PAES) stems from abnormal calf muscle development, particularly involving the gastrocnemius muscle. This condition can be:

• Congenital: Present from birth when either the calf muscle or nearby artery develops in an incorrect position during fetal development.
• Acquired: Develops later in life, typically due to an unusually enlarged calf muscle.

In both cases, the abnormal muscle structure puts pressure on the main artery behind the knee. This compression restricts blood flow to the lower leg and foot.

The reduced blood supply leads to symptoms during physical activity, most commonly pain and cramping in the back of the lower leg.

These symptoms occur because active muscles need more oxygen, but the compressed artery cannot deliver adequate blood flow to meet this demand.

Risk Factors

Several factors can increase a person’s chances of developing popliteal artery entrapment syndrome:

• Age: This condition typically affects younger individuals, especially those in their late teens and twenties. People over 40 rarely develop this problem.
• Gender: While anyone can develop this condition, young men face a much higher risk than women.
• Athletic Activities: People who participate in certain physical activities have an increased risk, including:
  • Runners
  • Cyclists
  • Weight trainers (especially those focusing on rapid muscle building)
  • High-intensity circuit training participants

Complications

Ongoing pressure on the popliteal artery may lead to artery narrowing (stenosis). This causes pain and cramping even during mild activities like walking.

If left untreated or undiagnosed, serious problems can develop:

• Damage to leg nerves and muscles
• Blood clots in the lower leg
• Possible popliteal aneurysm (artery bulging) in older patients

Older athletes with symptoms should be examined for aneurysms, which occur more frequently in older men. These complications can significantly affect mobility and quality of life if not properly addressed.