Genicular artery embolization

Osteoarthritis is the wear-and-tear type of arthritis. The smooth cartilage that cushions the ends of the bones thins out, and the knee becomes stiff, swollen and painful, especially with walking, stairs and standing up. It is one of the most common causes of pain and disability after age 50.

Cartilage has no nerves, so the pain comes from the tissues around it. In arthritic knees, the lining of the joint, called the synovium, becomes inflamed. The body responds by growing extra tiny blood vessels, and nerve fibers grow alongside them. These new vessels feed the inflammation, and the nerves send pain signals.

The knee is supplied by several small arteries called the genicular arteries. In genicular artery embolization (GAE), an interventional radiologist, a doctor who uses X-ray to guide thin tubes through the blood vessels, finds the branches feeding the inflamed areas and places tiny particles in them. This reduces the abnormal blood flow and the inflammation, which can ease pain for many months or longer. The normal blood supply to the knee is kept.

Before GAE we examine your knee and review recent X-rays. An MRI can help rule out other causes such as a torn meniscus that needs its own treatment. We also ask about your goals: walking farther, sleeping through the night, or delaying surgery.

When someone comes to me with a painful arthritic knee, I first want to know exactly where it hurts and what they want to get back to. On the X-ray I look at how much joint space is left, because GAE works best when there is still some cushion. During the procedure, the inflamed areas show up as a bright blush of tiny vessels, and those are the spots I treat. I am honest that GAE is a newer treatment, and I explain how it fits with therapy, injections and surgery.

Fabio Komlos, MD, interventional radiologist · About Dr. Fabio Komlos

Most people start with exercise, physical therapy, weight loss if needed, and pain relievers. When that is not enough, there are several options between pills and surgery. Genicular nerve ablation uses heat to quiet the small nerves that carry pain from the knee. GAE targets the inflamed tissue that creates the pain. Some people benefit from one, the other, or both at different times.

GAE does not stop arthritis from progressing or rebuild cartilage. It does not prevent a future knee replacement, and a replacement can still be done later if needed.

GAE is done at El Camino Hospital as an outpatient procedure. Do not eat for about 8 hours before, and bring an adult to drive you home. We usually ask that you avoid a steroid injection in that knee for several weeks before GAE. See before your procedure and blood thinners.

1. 1
   Getting ready

   A nurse places an IV and you are connected to heart, blood pressure and oxygen monitors. You receive moderate sedation so you are relaxed but can still talk with us.

2. 2
   A pinhole and a map

   The skin over the artery at the top of your thigh is numbed and a thin tube is placed with ultrasound guidance. A catheter is guided down to the knee, and contrast dye shows the genicular arteries on X-ray. We may ask you to point to the most painful spots.

3. 3
   Embolization

   A microcatheter, thinner than a strand of spaghetti, is placed in each artery feeding an inflamed area. Tiny particles are slowly released until the abnormal blush fades. You may feel a brief ache or coolness in the knee.

4. 4
   Closing and going home

   The catheter is removed and the puncture is closed with pressure or a small plug, with no stitches. After resting for a few hours, you walk out and go home.

On the angiogram, the inflamed parts of the knee lining look like a bright, cloudy blush of tiny vessels around the joint, fed by the thin genicular arteries. After embolization, the blush fades while the main arteries remain open.

1. Day of the procedure
   Rest with your leg straight for a few hours. No driving, alcohol or important decisions for the rest of the day.
2. Days 1 to 3
   Walk normally around the house. Avoid heavy lifting and hard exercise. Mild knee ache and bruising at the puncture site are common.
3. First 2 weeks
   Some people notice pink or purple patches of skin around the knee. These are expected and usually fade within days to a few weeks.
4. 1 to 3 months
   Pain relief builds gradually. Keep up physical therapy and exercise, which helps the result last.
5. Follow-up
   We check in with you to see how your pain and activity have changed and plan next steps if needed.

In published studies, about 2 in 3 people have a meaningful drop in knee pain that lasts at least a year, and many can walk and exercise more. GAE is still a newer treatment. Early randomized trials, including ones comparing GAE with a sham (placebo) procedure, have shown encouraging but mixed results, and larger studies are ongoing. Results are less reliable in very advanced arthritis.

GAE is generally safe, and serious complications are uncommon.