Genicular Artery Embolization (GAE) Procedure

Genicular artery embolization (GAE) is a minimally invasive treatment option for painful knee osteoarthritis. The procedure is meant to decrease abnormal blood flow around the knee joint to reduce pain and swelling.

UPMC interventional radiologists participated in early GAE clinical trials, making them among the most experienced GAE providers in the region — and among only a few centers in the Southwest Pa. area to offer the procedure.

As one of the nation’s leading GAE research centers, UPMC is recognized for its outstanding outcomes and cares for people who travel from out-of-state to receive expert GAE treatment.

What Is GAE?

Geniculate artery embolization (GAE) is a minimally invasive treatment option for painful knee osteoarthritis. The procedure is meant to decrease abnormal blood flow around the knee joint to reduce pain and swelling.

The procedure is performed through a small incision in your groin using thin tubes called catheters that are inserted into your blood vessels. Using real-time x-ray imaging guidance, a physician called an interventional radiologist will guide the catheters to the abnormal blood vessels in your knee and use small particles to block blood flow.

Conditions we treat with GAE

• Bleeding after knee replacement (hemarthrosis).
• Knee osteoarthritis.

Why Would I Need GAE?

GAE is not a cure for knee osteoarthritis, but it may be an effective way to manage pain and swelling symptoms for patients who:

• Have not found relief with medication or joint injections.
• Are not candidates for (or are not yet ready for) knee replacement surgery.

GAE also can be used to slow the progression of osteoarthritis and prevent it from getting worse. It is also a minimally invasive alternative to open surgery for people who have hemarthrosis (bleeding into the knee joint) after knee replacement surgery.

Who’s a Candidate for GAE?

You may be a candidate for GAE if:

• You have moderate to severe knee pain.
• You have mild-to-moderate arthritis that shows up on a knee x-ray.
• Conservative therapy, such as nonsteroidal anti-inflammatory medications or joint injections, has not helped your knee pain.
• You have bleeding in your knee joint.

GAE is not for patients who:

• Have advanced (bone-on-bone) osteoarthritis that shows up on a knee x-ray.
• Have a current infection or cancer.
• Are current or former smokers.
• Are good candidates for total knee replacement.

Alternatives to GAE

Alternatives to GAE include:

• Knee injections.
• Nerve ablation.
• Nonsurgical treatment, such as:
  • Activity changes to reduce knee strain.
  • Assistive devices, such as canes, crutches, or walkers.
  • Heat and/or ice.
  • Over-the-counter medications to manage pain.
  • Physical therapy.
• Partial or total knee replacement.

What Are the Risks and Complications of GAE?

As with any medical procedure, GAE comes with some risks.

GAE risks include:

• Bleeding.
• Blood clots.
• Infection.
• Nerve injury.
• Pain and swelling that doesn’t improve after surgery.
• Requiring a repeat GAE procedure.
• Temporary skin discoloration.

What Should I Expect From GAE?

Before: How to prepare for GAE

Before your procedure, you will meet with your care team and have a physical exam. Your care team will talk with you about how to prepare for your procedure.

Your care team may order tests, such as:

• Blood or urine tests — Your doctor may order blood work and urine studies to ensure you are healthy enough for the procedure and check for signs of illness or infection.
• CT scan — A computed tomography (CT) scan that creates images of the bones and structures in your knee.
• Electrocardiogram (ECG or EKG) — This test records the electrical activity of your heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and can sometimes detect heart muscle damage. EKGs are often performed before a procedure to ensure your heart is healthy and identify potential problems.
• MRI — MRI is a diagnostic procedure that combines large magnets, radio frequencies, and a computer to produce detailed images of organs and structures within your body.
• X-ray — Your doctor may order an x-ray to learn more about the condition of the bones and tissues in your knee.

Your doctor will explain the procedure to you and answer your questions. To prepare for the procedure, you should:

• Fast for a certain period before the procedure. Your doctor will tell you if you need to fast or how long to fast (usually overnight).
• Have any tests that your doctor recommends. For example, your doctor may request a blood test before the procedure to determine how long it takes your blood to clot.
• Tell your doctor if you are sensitive or allergic to any medications, iodine, latex, tape, or anesthetic agents (local and general).
• Tell your doctor about all medications (prescription and over-the-counter) and herbal or other supplements you are taking.
• Tell your doctor if you have any other health conditions. Your care team may need to take certain precautions during your procedure for your safety.
• Tell your doctor if you have a history of bleeding disorders or if you are taking any blood-thinning medications, aspirin, or other medications that affect blood clotting. You may need to stop some of the medications before the procedure.

On the day of your procedure, bring your photo ID and health insurance card(s). Leave valuables such as cash and jewelry at home.

GAE is typically performed as an outpatient procedure, so you can go home the same day. You must arrange for someone to drive you home after you are discharged.

How long does GAE take?

The GAE procedure takes one to two hours.

During your GAE

When you arrive at the hospital, you will meet with your care team for final preparations.

You will receive an IV in your hand or arm. You will have local anesthesia with twilight sedation, so you will feel relaxed and comfortable during the procedure and won’t feel any pain.

After you are positioned on a procedure table, your doctor will:

• Make a small incision (cut) in your groin to access a blood vessel.
• Insert a small, thin tube called a catheter into your blood vessel and guide it to the abnormal blood vessels in your knee using x-ray imaging guidance.
• Insert small objects that block blood flow to the abnormal blood vessels in your knee.
• Verify that blood flow is blocked using x-ray imaging guidance.
• Repeat the process as needed to block multiple abnormal blood vessels in your knee.
• Remove the catheter after abnormal blood vessels are blocked.
• Close your incision.

After your procedure, your surgeon will place a bandage over your incision and make sure your condition is stable.

Recovery after GAE

Most people return to normal activity within 1-2 days of their GAE procedure.

After your procedure is complete, you will be monitored in the recovery area. Your doctor will let you know when it is safe to go home. You will need someone to drive you home from the hospital after your discharge.

Before you go home, your doctor will tell you:

• How to care for your wound and watch for signs of infection or complications.
• What medications you need to take.
• When you should begin physical therapy.
• When to call your doctor or 911 if you have certain symptoms.
• When you should schedule your follow-up appointments, if one has not been scheduled already.
• When you can return to your normal activities, such as driving and bathing.

Your doctor will schedule follow-up appointments one month, three months, six months, 12 months, and 24 months after your procedure. Your one-month post-op appointment is typically an in-person visit, but the others can be scheduled as in-person or telemedicine visits.

When to call your doctor about complications

You should let your surgeon know if you have:

• A fever of more than 100.4°F.
• Difficulty breathing.
• Difficulty with walking or keeping your balance.
• New or increasing shortness of breath.
• Numbness, tingling, pain, swelling, or weakness in your leg.
• Pain, redness, bleeding, drainage, or increased swelling at your treatment site.
• Severe pain that does not respond to medication.

What’s the prognosis after GAE?

After the procedure, it will take time for inflammation and swelling to get better.

Most people notice pain relief about two weeks after their GAE procedure. By one month after their procedure, most people notice a significant reduction in their pain. After three months, most people will notice the maximum pain relief benefit from the procedure.

Many people also notice improved mobility and function after the procedure, enabling them to return to their everyday activities and hobbies. 

How long do the results of GAE last?

Research shows that pain relief after GAE may last up to four years. However, some people may experience pain relief that lasts for a shorter or longer period.

What’s the success rate of GAE?

Although the procedure is still being studied, multiple trials in the United States and abroad have shown excellent results in reducing participant pain. Recent clinical trials report that approximately 70% of patients have at least a 50% reduction in knee pain.

Some people with more severe knee osteoarthritis may not achieve the same pain-relief benefits from GAE. If symptoms persist or worsen, a partial or total knee replacement may be an option.

Why Choose UPMC for GAE?

When you choose UPMC for GAE, you will receive:

• Access to world-class, multidisciplinary expertise — Our world-renowned orthopaedic and interventional radiology experts work together to offer the latest, evidence-based treatments for knee pain.
• Advanced diagnostic care — We’ll find the cause of your knee pain and work with you to develop a comprehensive treatment plan.
• A full range of treatment options — We offer nonsurgical care, as well as minimally invasive, robotic, and traditional surgical approaches, depending on your individual care needs.

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By UPMC Editorial Staff. Last reviewed on 2025-02-04 by Anish Ghodadra, MD.