What is PAES?
Popliteal artery entrapment syndrome (PAES) is a rare condition that most commonly affects young athletes. It occurs when your calf muscle presses against the primary artery in the back of your knee due to unusual size or positioning. This makes it difficult for blood to get to your lower leg.
Popliteal Artery Entrapment Syndrome Types
There are two primary types of popliteal artery entrapment syndrome, categorized according to their causes:
Congenital causes. Congenital variations of PAES are present at birth. The path of the artery is changed by the shape of a muscle behind the knee. Sometimes, congenital PAES doesn't cause any symptoms, but in other cases, it can severely compress and eventually block the popliteal artery.
Developmental causes. In cases of developmental PAES, the muscles are in the correct place, but they start to compress the popliteal artery as they grow.
Popliteal Artery Entrapment Syndrome Symptoms
Most people with popliteal artery entrapment syndrome experience pain in the back of their calf muscle when they exercise, though the pain usually subsides following rest.
Other symptoms may include:
- Coldness in your feet following exercise
- Paresthesia (tingling or burning sensations) in your calf muscle
- Numbness in your calf
Additionally, if the popliteal vein near the popliteal artery is compressed by the calf muscle, you may experience:
- Heaviness in your leg
- Swelling in your lower leg around your calf
- Cramping in your lower leg at night
- Deep vein thrombosis (blood clots in your lower leg)
- Changes in the color of your skin around your calf muscle
Complications of Popliteal Artery Entrapment Syndrome
In cases where the popliteal artery is under pressure for a long period of time, the artery can narrow. If this happens, you may experience pain and cramping even when casually walking. If your case of popliteal artery entrapment syndrome is severe or goes undiagnosed for a long time, the nerves and muscles in your legs may become damaged, and blood clots may develop in your lower leg.
People with congenital popliteal artery entrapment syndrome may need to have their abnormal muscle slips removed so that the popliteal artery isn't damaged over time. If your popliteal artery entrapment syndrome isn't treated before your popliteal artery becomes damaged, you may experience constant pain when you walk. In extremely rare cases of extensive damage, you may even need to have your leg amputated. However, this is highly unlikely.
How Is Popliteal Artery Entrapment Syndrome Treatment Diagnosed?
Doctors can have a hard time diagnosing popliteal artery entrapment syndrome because it's unusual for young people to have diseases that affect their blood vessels. Additionally, many other conditions have similar symptoms, including:
- Chronic compartment syndrome of the lower extremities
- Knee joint pain
- Other calf muscle problems
PAES is usually diagnosed with tests that measure the blood flow in your lower leg, such as:
- A CT scan with contrast
- An ultrasound
- An angiogram
Popliteal Artery Entrapment Syndrome Treatment
Popliteal artery entrapment syndrome is usually treated with surgery to remove a small part of your muscle and restore normal blood flow to your leg. The surgery takes about an hour, and you'll be put to sleep with general anesthesia during the procedure. The surgery is very successful for most people. Over 90% who receive it report that their symptoms improved afterward.
Your surgeon will make an incision just below your knee or in the back of your knee. This will release your calf muscle and provide more room for your artery. The surgery will also seek to prevent your muscle from pressing on the artery in the future.
If you have an advanced case of congenital popliteal artery entrapment syndrome or your popliteal artery has been damaged, it may also need to be cleaned out and patched, and you may even need a bypass to restore blood flow around the blocked artery.
The only nonsurgical treatment for popliteal artery entrapment syndrome is an injection of botulinum toxin A. This will temporarily paralyze the muscle pressing on the popliteal artery, causing it to shrink. The injection will lose its effect after three to six months, though, and the symptoms will return if the calf muscle doesn't shrink sufficiently during that time. Injections are not typically as successful as surgery. One year after treatment, less than 60% of cases were reported to be successful.
Risk Factors for Popliteal Artery Entrapment Syndrome
You're at an increased risk for developing popliteal artery entrapment syndrome if you:
- Are young (usually an older teenager or in your 20s)
- Were assigned male at birth
- Engage in strenuous exercises such as running, cycling, heavy weight training, or intense circuit training
Prognosis for Popliteal Artery Entrapment Syndrome
If your symptoms aren't bothering you, you may not need treatment for your popliteal artery entrapment syndrome. Your healthcare provider may simply monitor your condition while you limit your exercise.
For more severe cases, surgery is often successful, and symptoms don't return in over 90% of cases. Most athletes can return to their regular activities after undergoing surgery and fully recovering.
Recovery time following surgery lasts about four to six months. Additionally, after your surgery, you'll spend at least one night in the hospital. Following that, you'll work with a physical therapist on an outpatient basis for two weeks. You'll continue to engage in the strengthening exercises that they teach you until you're fully recovered.
You'll also need to follow up with your healthcare provider in one month, six months, and 12 months. During these appointments, your healthcare provider will likely perform an ultrasound, checking on your repaired popliteal artery and monitoring your blood pressure in your feet. If your artery is functioning normally, you won't have to return for additional follow-ups unless you experience further problems.