What is GAE?

Genicular artery embolization (GAE), or embolization of the knee, is a new minimally invasive alternative to knee replacement surgery. It is a procedure that provides immediate and long-term pain relief without having to have surgery, It is intended for patients with osteoarthritis (OA) and works by reducing the blood flow to the lining of the knee where all the inflammation from the arthritis causes the pain. This is a procedure that is performed by an endovascular specialist, who is a specialist physician who uses X-rays and other imaging technologies to see inside the body and treat diseases without having to do open surgeries.

Treatment for:

Osteoarthritis of the knee

Detailed anatomical diagram of the knee joint, showing key structures such as bones, ligaments, and cartilage, designed for educational or medical presentations.

Improves Pain by Eliminating the Information

Instead of using medications like Motrin and Tylenol to control the inflammation in the joint, this simple procedure eliminates the inflammation by blocking the blood flow to the lining of the knee, known as synovium, that is inflamed. Research is showing that this is an effective way to manage pain with the risk of major knee replacement surgery. In an article published in the Society of Interventional Radiology in March 2021, average pain scores decreased from eight out of ten before GAE to three out of ten within the first week.

How is GAE Performed?

GAE is performed with the need of general anesthesia and having to put the patient to in sleep. Instead, it is performed with moderate ‘twilight’ sedation as an outpatient procedure just like having a colonoscopy or breast needle biopsy type procedure. This means that the patient will go home immediately after the procedure without a long recovery from surgery. The entire procedure usually only takes one to two hours to perform and is done without making any surgical incisions. Instead, it is performed via a small IV started in the thigh. This involves inserting a small catheter (a thin hollow tube) into the artery of the patient’s upper thigh and with the use of X-ray guidance, the catheter is placed into the arteries supplying the lining of the knee. An angiogram is then performed that shows where the inflammation is happening. Tiny particles are then injected through the catheter into these small arteries thereby reducing the blood supply to the synovium (knee lining). This then reduces the inflammation associated with arthritis, which eliminates the pain.

Initial (left) and final (right) angiograms of the knee after embolization. A circular marker was placed at the site of pain. The reduced blood flow at the site of pain after embolization reduced inflammation of the knees.

Initial (left) and final (right) angiograms of the knee after embolization. A circular marker was placed at the site of pain. The reduced blood flow at the site of pain after embolization reduced inflammation of the knees.

Find out if you are a candidate

What to Expect After the GAE Procedure?

All patients go home the same day after a few hours in the recovery area. Pain relief usually begins to be noticed in two weeks, as the inflammation in the lining of the knee subsides and goes away thereby relieving the knee pain associated with the arthritis.

How do you know if you are a Candidate for GAE?

This is a good option for patients who have pain and have failed physical therapy and for those whose pain medications are no longer working. Treatments such as anti-inflammatory medications or knee injections usually only work for so long in controlling pain. GAE is also indicated in anyone who does not wish to undergo or is ineligible for knee replacement surgery.

The following are some guidelines for those thinking of GAE

  • Age: 45-80 years
  • Moderate to severe pain
  • Osteoarthritis based on x-ray findings 
  • Knee tenderness that can be localized
  • Failed conservative treatment (NSAIDs/PT/joint injection)

Benefits of GAE for Knee Pain

  1. No incisions so no chance of having a knee infection after the procedure
  2. Outpatient procedure, back home, and at work the next day
  3. Very little to no risk for anesthesia-related complications such as heart attacks and strokes during the procedure
  4. Diabetics with high A1C levels can behave the procedure done

Recovery from a GAE Procedure

Patients go home the same day as the procedure after a few hours of recovery time. You may have a small bruise with some mild tenderness in the groin where the IV is started. Taking it easy the day of the procedure is recommended, however, by the following day we recommend returning to light activity with no heavy exercise or lifting greater than 15lbs. One week after the procedure the patient may return to heavy activity and exercise. Patients usually notice a significant improvement in their pain 1-2 weeks after the procedure as the inflammation in the joint goes away.

Safety Profile

Safety is an important aspect of any medical procedure. Research studies have examined the safety profile of GAE, including the chances of complications such as bleeding, infection, or nerve damage. Overall, GAE has shown to be a safe procedure with negligible rates of complications when performed by experienced interventional physicians. The most common complication is temporary discoloration of the skin at the knee. Less than 0.05% of patients have described having developed small skin ulcers which all healed on their own within a few weeks. Less than 0.01% of patients have had damage to the bone in the knee or other serious complications requiring surgery to fix it.

Efficacy of GAE (How well does it work?)

Several research studies have investigated the effectiveness of GAE in relieving chronic knee pain. Technical success rates in being able to reduce inflammation are >99%. Initial research studies suggest that GAE can provide significant pain relief and functional improvement in patients with chronic knee pain, particularly those who have not responded to other conservative treatments like physical therapy or medications. In general patients with mild to moderate pain from Osteoarthritis have shown the most benefit from GAE with 75-85% of patients having significant pain relief after the procedure. However, benefits have also been described in patients with advanced arthritis who cannot have surgery.

Long-term Outcomes (Does the Pain Relief Last?)

Long-term follow-up data are important for assessing the longevity of pain relief and functional improvement achieved with GAE. GAE has been shown to provide pain relief for up to 12 months or longer in multiple research studies.

Mechanisms of Action (How does it work?)

Osteoarthritis (OA) is a degenerative disease of the synovial joints (Joints lined with fluid) characterized by progressive chondral (linning) wear and bony remodeling. There is a strong chronic inflammatory process that follows with the development of abnormal blood vessels that subsequently increase the blood flow to the joint lining that delivers inflammatory cells to the knee to help the healing process.  This is seen clinically as joint pain and dysfunction. GAE can eliminate this inflammatory process by occluding the abnormal vessels that develop in response to chronic inflammation. Occlusion of the vessels limits the progression of synovitis (inflammation) and the infiltration of inflammatory cells in the synovium thereby decreasing inflammation and creating pain relief

Published Research Studies

Epelboym, Yan, et al. “Genicular artery embolization as a treatment for osteoarthritis-related knee pain: a systematic review and meta-analysis.” CardioVascular and Interventional Radiology 46.6 (2023): 760-769.

Taslakian, Bedros, et al. “Genicular artery embolization for treatment of knee osteoarthritis pain: Systematic review and meta-analysis.” Osteoarthritis and Cartilage Open 5.2 (2023): 100342.

Bhatia, Ansh, and Shivank Bhatia. “The short-to-midterm outcomes of geniculate artery embolization for mild-to-moderate osteoarthritis of the knee: a systematic review.” Journal of orthopaedics (2023).

Landers, Steve, et al. “Genicular artery embolization for early-stage knee osteoarthritis: results from a triple-blind single-centre randomized controlled trial.” Bone & Joint Open 4.3 (2023): 158-167.

Sun, Changhao, et al. “Genicular artery embolization for the treatment of knee pain secondary to mild to severe knee osteoarthritis: One year clinical outcomes.” European Journal of Radiology 175 (2024): 111443.

Gill, Stephen D., et al. “Outcomes after Genicular Artery Embolization Vary According to the Radiographic Severity of Osteoarthritis: Results from a Prospective Single-Center Study.” Journal of Vascular and Interventional Radiology 34.10 (2023): 1734-1739.

Taslakian, Bedros, et al. “Genicular artery embolization for treatment of knee osteoarthritis: interim analysis of a prospective pilot trial including effect on serum osteoarthritis-associated biomarkers.” Journal of Vascular and Interventional Radiology 34.12 (2023): 2180-2189.