This emerging treatment could help people avoid knee replacement surgery

The procedure was "remarkably" successful. That is how 74-year-old Cynthia Schraf-Fletcher describes genicular artery embolization (GAE), a minimally invasive treatment designed to reduce chronic knee pain. Nearly a year after having the outpatient procedure on her right knee, she says the result feels almost the same as the total knee replacement she previously underwent on her 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 everyday activities that once came with substantial discomfort are now much easier. Gardening, riding a stationary bicycle, and enjoying other favorite activities all involve far less pain. A New Option Between Injections and Knee Replacement Genicular artery embolization works by reducing blood flow to inflamed areas inside the knee. The goal is to calm inflammation, which can in turn 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. "For treating osteoarthritis in the knees, we often think of medications, physical therapy, maybe a steroid injection, and then on the far end of the spectrum is a total knee replacement. There really hasn't been anything for patients in between," Casadaban, a vascular interventional radiologist, says. "GAE is a promising minimally invasive procedure that may fill that spot for people who have failed conservative treatments but are not yet ready to have a major surgery." Osteoarthritis is a degenerative joint disease in which cartilage and other structures inside a joint gradually break down. In the knee, that 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 GAE. Patients with more advanced disease can also undergo the procedure, but the benefits may not last as long. "We find about 70% of patients have phenomenal results. They cut their pain scores in half, sometimes more. We have a few patients with no pain at all after the procedure," Casadaban says. "Patients that have tried a lot of other treatments and haven't had pain relief are happy to get back to their normal activities." For Schraf-Fletcher, the chance to avoid another major knee operation was especially appealing. After experiencing complications from her earlier knee replacement surgery, she says she was eager to try GAE and is glad she did. How the Procedure Works GAE typically takes 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 imaging and contrast dye, which allows the doctors to see the blood vessels clearly. Once the catheter reaches the genicular arteries around the knee, the team releases tiny beads into abnormal blood vessels associated with the painful, inflamed areas identified by the patient. Those beads reduce blood flow to the targeted vessels. Because the procedure does not involve replacing the joint or making a large surgical incision, recovery is generally much shorter than after knee replacement. Patients are monitored for several hours afterward and typically return home the same day. They are usually advised to take it easy for the next few days. A Procedure With Growing Interest GAE was first developed in Japan a little more than a decade ago and has since attracted increasing attention around the world. In the United States, the FDA has granted "breakthrough device status" to a number of devices used in this area since 2021. The designation is intended to speed the development and review of certain medical technologies that could offer meaningful advantages for patients. Early research on GAE has also produced encouraging results. "The theory is that GAE reduces inflammation inside the knee joint, and symptom relief can last years," Casadaban says. "Four-year data published in Japan shows that if you have one outpatient procedure, your pain relief can last for those four years. In the U.S., we now have two-year data, which shows that if you have a good response, pain relief can last two years. That really speaks to the theory that we're hopefully modifying something in the joint." The possibility that a single outpatient treatment could provide relief lasting several years is one reason researchers are closely studying what happens inside the knee after GAE. Researchers Are Testing How GAE Changes the Knee Casadaban is leading clinical trials at CU Anschutz aimed at learning more about the treatment. One study is looking at 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 inside 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 may 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 into treatments for other painful conditions. Casadaban says similar approaches are being explored for problems including 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.