Do you feel a sharp ache, tightness, or numbness in your calf when you run, exercise, or walk fast?
Does this pain fade away after a short rest, only to return the moment you start moving again? If this sounds familiar, you might want to learn about a rare condition called Popliteal Artery Entrapment Syndrome, or PAES for short. Do not worry. We will walk through everything you need to know in simple, plain English.
- PAES happens when a muscle presses on your main leg artery behind your knee.
- It mostly affects young, active people and runners between the ages of 15 and 25.
- Symptoms include calf pain, cramping, and numbness during exercise that stops with rest.
- Doctors use special scans and blood pressure tests to diagnose this condition accurately.
- Surgery is often the most successful treatment to restore normal blood flow to your leg.
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What is Popliteal Artery Entrapment Syndrome?
Simply put, Popliteal Artery Entrapment Syndrome is a rare blood vessel condition. It mostly affects young, active people who play sports.
Your popliteal artery is the main blood pipe that runs from your thigh down past the back of your knee into your calf. In this condition, that important artery gets squeezed by a nearby muscle.
Think of your blood vessel like a water hose. The artery supplies blood down to your lower leg.
In PAES, your calf muscle connects to your thigh bone in a slightly unusual way. When you point your foot downward, your calf muscle tightens and squeezes the artery.
When you exercise, this ongoing squeeze causes the artery to go into spasms. Your lower leg then receives less blood than it needs.
As a result, waste products like lactic acid build up in your muscles and nerves. That is why your calf feels heavy, tight, tired, or numb while you work out.
The good news is that these symptoms usually fade within three to five minutes of stopping exercise. However, if you do not treat it, the pinching can happen faster and last longer over time.
Who is Most Likely to Get PAES?
This condition generally affects young athletes between the ages of 15 and 25. People who take part in running sports face the highest risk.
Common sports linked to this condition include track and field, cross country, soccer, lacrosse, and field hockey. Imagine a high school runner or a soccer player who uses their legs intensely every day. Because they repeat these movements constantly, they carry a higher chance of developing this issue.
How Common is PAES?
PAES is actually a very uncommon medical condition. Experts estimate that it affects less than one percent of the general population. Because it occurs so rarely, exact numbers are hard to pin down.
Are There Other Conditions That Look Like PAES?
Yes, other conditions can cause similar symptoms. Chronic Exertional Compartment Syndrome, or CECS, is a more common exercise-related muscle and nerve condition.
CECS can cause pain and swelling in your lower legs or arms during physical activity. While CECS can affect almost anyone, it is most common in young runners and athletes who do high-impact sports.
Sometimes, a person with PAES might also have CECS at the same time. Studies show that about 5 percent of people who do not get relief from PAES treatments turn out to have CECS as well.
What is the Difference Between PAES and CECS?
Your doctor will use different tests to tell these two conditions apart.
- For PAES: Your doctor measures your blood pressure at rest and checks if it drops after exercise.
- For CECS: Your doctor measures the pressure inside the four compartments of your lower leg before and after exercise. In CECS, the pressure inside these compartments rises to abnormal levels.
What Does PAES Feel Like?
When you exercise, you might notice specific symptoms in your calf or foot area. Common signs include cramping, tiredness, a heavy feeling, muscle spasms, numbness, and a burning sensation.
These symptoms typically disappear after resting for three to five minutes. Yet, as mentioned earlier, untreated symptoms can appear earlier during your workouts and take longer to resolve.
What Causes PAES?
Two main types of compression cause this condition. Knowing the cause helps your medical team plan the right care.
Anatomic compression accounts for about 10 percent of cases. This type appears more often in males and usually affects only one leg.
Functional or physiologic compression occurs more often in females. More than 90 percent of these cases affect both legs.
Anatomic Compression.
This happens when a part of your calf muscle sits above or below your popliteal artery. Sometimes, a fibrous band of tissue can damage the artery over time.
This damage can lead to a sore or ulcer on the artery wall, a blood clot, or a complete blockage of the artery and the vessels below it. Medical experts recognize four distinct anatomical variations in how the muscle relates to the artery.
Functional or Physiologic Compression.
In this type, your muscles form in a normal way. However, the muscle attaches slightly higher up on your thigh bone or inside a groove near your knee.
Because of this placement, pointing your foot downward pulls the muscle inward to squeeze the artery. Sometimes, a deeper muscle behind the artery called the popliteal muscle also causes this squeeze. Researchers note that functional compression does not usually cause lasting physical damage to the artery wall.
How Do Doctors Diagnose PAES?
A vascular specialist is the best doctor to diagnose this condition properly. Your doctor will examine you and check for pulses in your foot and behind your knee.
They may also check if your pulse changes when you push or pull your foot against resistance. If you have PAES, your doctor might feel normal pulses while you rest. However, those pulses may weaken or disappear when you exercise or move your foot in certain directions.
What Tests Check for PAES?
Diagnostic tests measure blood flow through your knee, leg, and foot. These imaging tests help reveal if your artery is normal, if a sore is forming, if blood clots are present, or if the artery is swollen and bulging. They also show whether a muscle is pressing against the vessel.
| Test Name. | What It Does. |
|---|---|
| Ankle-Brachial Index with Exercise. | Compares blood pressure in your arms and legs before and after exercise to spot restricted blood flow. |
| Duplex Ultrasound. | Uses sound waves to capture images of blood flow while your foot rests or points downward. |
| CTA Scan. | Uses a special dye and CT imaging to examine your leg arteries and muscle positions clearly. |
| MRA Scan. | Uses a magnetic field and radio waves to create detailed pictures of your blood vessels and surrounding tissue. |
How is PAES Treated?
Your doctor can perform surgery to remove a small piece of the calf and popliteal muscles. This removes the pressure on the artery and lets blood flow normally to your leg again.
The surgery usually takes about an hour. Doctors perform this procedure while you are completely asleep under general anesthesia.
In severe cases where anatomic compression damages or blocks the artery, your surgeon may need to clean out the artery, patch it, or create a bypass graft to route blood around the blocked spot.
Surgery is the most successful treatment for PAES, with great results for most people. More than 90 percent of patients who undergo surgery experience a major reduction in symptoms.
For people with functional PAES, doctors sometimes use botulinum toxin type A injections as a non-surgical option. Guided by ultrasound or CT imaging, your doctor injects Botox or Dysport into the muscle causing the squeeze. This temporarily paralyzing injection aims to relax and shrink the muscle.
However, this relief only lasts for three to six months. If the muscle does not shrink permanently, symptoms can return. This treatment is successful in fewer than 60 percent of patients after one year.
How Long Does Recovery Take After Treatment?
Full recovery after surgery can take anywhere from four to six months. You will typically spend one night in the hospital after the procedure.
During the first two weeks, you will need to do gentle physical therapy like stretching exercises. After those two weeks, you can move on to strength and conditioning exercises until you heal completely.
What is the Outlook for Someone with PAES?
If you have functional popliteal entrapment and your exercise pain is mild, you might choose to limit your workouts while your doctor monitors your condition.
As mentioned before, surgery boasts a success rate of over 90 percent with a low chance of returning symptoms. Many athletes return to their regular activities successfully after surgery.
If you have anatomic entrapment, doctors strongly recommend surgery to remove the abnormal muscle tissue. Delaying treatment when you have anatomic PAES can cause lasting damage to your artery.
If left untreated for too long, severe cases can lead to chronic leg pain while walking. In very rare instances, extreme damage can even threaten the limb, though this happens only on rare occasions.
When Should You See a Doctor Again?
After your surgery, your doctor will want to schedule follow-up visits at one month, six months, and twelve months.
During these visits, your medical team will perform an ultrasound on your repaired artery and check the blood pressure in your legs. Once your artery returns to normal and you have no lingering symptoms, you will not need routine visits unless symptoms return or you needed a bypass graft.
Seek emergency medical care right away if your leg suddenly turns pale, feels ice cold, becomes completely numb, or causes severe, sudden pain that does not go away with rest. These signs can mean blood flow to your leg has stopped completely.
What Questions Should I Ask My Doctor?
- Do I have anatomic PAES or functional PAES?
- Do you recommend surgery for my specific condition?
- What kind of physical therapy will I need after treatment?
- How soon can I safely return to running and playing sports?
References & Further Reading:
- Cleveland Clinic. Popliteal Artery Entrapment Syndrome (PAES): Overview & Treatment.
- Mayo Clinic. Popliteal artery entrapment syndrome: Diagnosis and management guidelines.
- NHS UK. Leg pain during exercise and vascular health conditions.
- Centers for Disease Control and Prevention (CDC). Staying active safely and recognizing circulation issues.
- National Institutes of Health (NIH) / PubMed. Popliteal artery entrapment syndrome in athletes: a systematic review.
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