• Posted August 22, 2025

Artery-Blocking Procedure Relieves Knee Arthritis Pain

Wear-and-tear knee arthritis might be made less painful by a surgical procedure that limits blood flow to the joint, a new pilot study says.

As a person’s knee breaks down, the pain is made worse by the growth of small blood vessels that increase blood flow to the joint, researchers said.

The new procedure involves blocking this blood flow by placing hydrogel beads in arteries that feed the knee’s lining, researchers report in the Journal of Vascular Interventional Radiology.

More than 60% of 25 men and women who underwent the procedure experienced significant improvements in their knee pain by one year later, results show.

“This procedure is particularly suited to those patients who are either not yet ready for knee replacement surgery or for whom surgery is not an option because of age or other risk factors, such as obesity, uncontrolled diabetes or heart disease, or smoking,” senior researcher Dr. Ryan Hickey, section chief of vascular and interventional radiology at NYU Grossman School of Medicine, said in a news release.

An estimated 24 million cases of knee arthritis are diagnosed each year in the United States, Hickey said, and that number is expected to grow with the aging population.

The wear-and-tear of the knee joint causes inflammation, which in turn triggers the growth of new blood vessels, researchers said. This causes abnormal blood flow to the joint, increasing the amount of immune cells that create even more inflammation and pain.

The procedure, called genicular artery embolization, is performed under mild sedation in less than two hours by an interventional radiologist, researchers said.

The microgel beads used are 250 micrometers in diameter. By comparison, a human hair is 50 to 70 micrometers, and a grain of fine beach sand is 90 micrometers.

Doctors used video X-ray to guide a catheter to the precise knee artery selected for embolization, and then block blood flow by placing the hydrogel. 

All the patients in the study had moderate to severe knee osteoarthritis that hadn’t responded to treatments like steroid injections, excess fluid removal, injections of platelet-rich plasma or physical therapy. Their ages ranged from 50 to 78, and their procedures were performed between January 2021 and January 2023.

A year later, 3 of every 5 patients had improvement in scores for knee pain, stiffness, and their ability to bend, stand up, and climb or descend stairs, researchers said. 

None of the patients experienced any severe side effects, results show.

“Our study shows that genicular artery embolization is a safe and effective, minimally invasive treatment for those with moderate to severe symptomatic knee pain tied to osteoarthritis,” Hickey said.

“This work also provides evidence that genicular artery embolization is offering more than just pain relief and could be modifying the diseases process itself,” he added.

Besides a reduction in knee pain, the procedure also appeared to spark an average 12% decline in blood levels of vascular endothelial growth factor (VEGF), a protein that promotes the growth of new blood vessels.

There also was an average 15% decrease in interleukin 1 receptor agonist (IL1Ra), a protein known for its role in controlling inflammation.

Researchers plan to further investigate precisely why cutting off blood flow reduces inflammation and relieves pain.

More research also is needed to establish how long the procedure’s benefits last and which patients are most likely to benefit, Hickey added.

More information

The Arthritis Foundation has more on knee osteoarthritis.

SOURCES: NYU Langone Health, news release, Aug. 14, 2025; Journal of Vascular Interventional Radiology, Aug. 12, 2025