The procedure was “remarkably” successful.
That’s how Cynthia Schraf-Fletcher, 74, describes genicular artery embolization (GAE), a minimally invasive treatment designed to reduce chronic knee pain. Nearly a year after undergoing the outpatient procedure on his right knee, he says the result feels almost the same as the total knee replacement he previously underwent on his left knee.
“I couldn’t be more pleased,” says Schraf-Fletcher, who turned to Leigh Casadaban, MD, MS, assistant professor of radiology at the University of Colorado Anschutz School of Medicine, for the treatment.
She says that everyday activities that once involved great discomfort are now much easier. Gardening, riding a stationary bike, and enjoying your other favorite activities involve much less pain.
A new option between injections and knee replacement
Genicular artery embolization works by reducing blood flow to the swollen areas within the knee. The goal is to calm inflammation, which in turn can reduce swelling and pain.
That makes the procedure potentially useful for people with osteoarthritis who have exhausted simpler options but are not yet ready for major surgery.
“To treat osteoarthritis in the knees, we often think about medications, physical therapy, maybe a steroid injection, and then, at the other end of the spectrum, a total knee replacement. There really hasn’t been anything for patients in between,” says Casadaban, a vascular interventional radiologist. “GAE is a promising minimally invasive procedure that can fill that gap for people who have failed conservative treatments but are not yet ready to undergo major surgery.”
Osteoarthritis is a degenerative joint disease in which the cartilage and other structures within a joint gradually break down. In the knee, this process can cause pain, stiffness, inflammation, and difficulty walking or exercising.
According to Casadaban, people with mild to moderate knee osteoarthritis tend to be the best candidates for CSD. Patients with more advanced disease can also undergo the procedure, but the benefits may not last as long.
“We find that about 70% of patients get phenomenal results. They reduce their pain scores by half, sometimes more. We have some patients who don’t feel any pain after the procedure,” says Casadaban. “Patients who have tried many other treatments and have not received pain relief are happy to return to their normal activities.”
For Schraf-Fletcher, the chance to avoid another major knee operation was especially appealing. After experiencing complications from her previous knee replacement surgery, she says she was eager to try GAE and is glad she did.
How the procedure works
GAE usually lasts one to two hours and is performed under conscious sedation. That means the patient is relaxed and comfortable, but is not placed under full general anesthesia.
An interventional radiology team begins by making a small incision in the crease of the leg. A very thin tube called a catheter is then guided through the femoral artery using X-ray images and contrast dye, allowing doctors to see the blood vessels clearly.
Once the catheter reaches the genicular arteries around the knee, the equipment releases small beads into the abnormal blood vessels associated with the swollen and painful areas identified by the patient. Those beads reduce blood flow to the target vessels.
Because the procedure does not involve replacing the joint or making a large surgical incision, recovery is usually much shorter than after knee replacement.
Patients are monitored for several hours afterwards and typically return home the same day. They are generally advised to take it easy for the next few days.
A procedure with growing interest
GAE was first developed in Japan just over a decade ago and has since attracted increasing attention around the world.
In the United States, the FDA has granted “breakthrough device status” to several devices used in this area since 2021. The designation is intended to accelerate the development and review of certain medical technologies that could offer significant benefits to patients.
Early research on GAE has also produced encouraging results.
“The theory is that GAE reduces inflammation within the knee joint and symptom relief can last for years,” says Casadaban. “Four years of data A study published in Japan shows that if an outpatient procedure is performed, pain relief can last four years. In the US, we now have two years datawhich shows that if there is a good response, pain relief can last two years. “That really speaks to the theory that we’re hopefully tweaking something in the joint.”
The possibility that a single outpatient treatment could provide relief that lasts several years is one reason why researchers are closely studying what happens inside the knee after SAE.
Researchers are testing how GAE changes the knee
Casadaban leads clinical trials at CU Anschutz aimed at learning more about the treatment.
A study is analyzing changes in fluid in the knee in people undergoing GAE. By examining those changes, researchers hope to better understand how the procedure affects inflammation and other processes within the joint.
Another study is evaluating a new temporary treatment device called Nexsphere-F. The device is placed in the arteries and temporarily blocks small blood vessels in the knee that can contribute to inflammation and pain.
Osteoarthritis affects millions of people each year and can develop in many joints throughout the body. For now, GAE is being used to treat knees, but the same general strategy is beginning to expand to treatments for other painful conditions.
Casadaban says similar approaches are being explored for problems such as frozen shoulder, tennis elbow and plantar fasciitis.
If ongoing studies continue to show lasting benefits, GAE could become an important option for patients caught between conservative treatments and major joint surgery.