New embolization treatment under study aims to relieve osteoarthritis knee pain

Stock knee pain patient
People with osteoarthritis in their knees can try several different treatments to conquer the pain, swelling and stiffness that accompany this degenerative disease. Pain medications, steroid injections, physical therapy and nerve ablation all provide relief, but eventually some patients need surgery to replace their knee’s damaged cartilage and bone.

Now, doctors at the University of Chicago Medicine are exploring whether a minimally invasive treatment that involves sealing off problematic arteries in the knee can help patients for whom a knee replacement may not be an option. UChicago Medicine is one of the first in the country to perform the procedure, as well as the only institution in the Midwest currently conducting a clinical trial on the method.

“There’s a huge treatment gap for people whose pain isn’t really well controlled with medications, but who also aren’t ready for surgery,” said interventional radiologist Osman Ahmed, MD. “This is not necessarily a cure, but rather another treatment that can hopefully give patients pain relief.

Ahmed is the principal investigator for a pilot study using genicular artery embolization (GAE) to treat poorly controlled pain in osteoarthritis in the knees. Genicular is an anatomical term meaning of or related to the knee.

Osteoarthritis of the knee occurs when protective cartilage in the joint wears away. The pain can become severe if there is no cartilage left and the bones essentially rub against each other.

“Patients can experience shooting pain every single time they put weight on that knee, which is basically every step you take,” said Magdalena Anitescu, MD, PhD, an interventional pain medicine specialist and anesthesiologist. Anitescu is the study’s co-principal investigator.

When nonsurgical treatments fail, however, many patients may not be ready for knee surgery. Patients who are on dialysis or who have severe obesity or poorly controlled diabetes may not be eligible for knee replacement surgery.

“Knee replacement is a wonderful procedure that can give people their life back and allow them to get back to doing activities they weren’t able to do,” said orthopaedic surgeon Tessa Balach, MD, who specializes in knee replacement surgery. “I think GAE may be a great option for those who aren’t ready for a knee replacement yet, and this is not a small group.”
GAE procedure
The bright colors in the image on the right denote blood flow and inflammation in the area of the knee. The image on the left shows the same area after a GAE procedure.
Embolization — the blocking of blood vessels — has been used for decades to cut off the blood supply to tumors and to stop internal bleeding, including in the knee. With GAE, a doctor uses an X-ray to guide a tube less than 1 millimeter in width into the arteries of the knee, injecting dye to determine which arteries are abnormal. Biocompatible microscopic beads are then injected to block those specific vessels.

“The inflammation is what drives nerve growth and pain in the knee area,” said Ahmed. “So if we can reverse that process of blood vessel growth and inflammation, then we can reverse the pain.”

More research is needed on how long this experimental treatment lasts; Ahmed said early data suggests at least a year.

Patients are moderately sedated for the procedure, and there is a risk of bleeding and infection as well as temporary skin discoloration and pain after GAE.

The team is planning a larger study involving 100 patients this spring that will compare the effectiveness of GAE to nerve ablation for knee osteoarthritis; half of the patients will receive GAE, while the remainder will be given nerve ablation.

“This might potentially be a Pandora's box of possibilities if GAE works well,” said Ahmed. “We might be able to apply the technique to diseases of other joints and tendons.”

The research is a multidisciplinary effort by doctors in the Departments of Radiology, Anesthesia and Critical Care, and Orthopaedic Surgery and Rehabilitation Medicine. “The study is incredibly collaborative within the institution,” said Ahmed.

Patients who are interested in learning more about the procedure can contact Ahmed at
Magdalena Anitescu, MD, PhD

Magdalena Anitescu, MD, PhD

Magdalena Anitescu, MD, PhD, is a leader in the field of anesthesia and interventional pain medicine.

Tessa Balach

Tessa Balach, MD

As an orthopaedic oncologist, Tessa Balach, MD, provides comprehensive surgical care for bone and soft tissue tumors.

Learn more about Dr. Balach