A minimally invasive procedure that blocks abnormal blood vessels around the knee may offer lasting relief for people with osteoarthritis who have exhausted standard treatments.
For millions of people with knee osteoarthritis, treatment options often fall into an uncomfortable middle ground: medications and injections may no longer provide enough relief, while joint replacement surgery can be too risky, undesirable, or premature.
New research suggests a minimally invasive procedure that targets abnormal blood vessels around the knee could help bridge that gap, providing significant and lasting reductions in pain while improving mobility and quality of life.
The findings, published in Radiology, show that embolization using rapidly resorbable gelatin-based microspheres was safe and effective in patients with osteoarthritis-related knee pain. Knee osteoarthritis affects more than 365 million adults worldwide and is among the leading causes of disability, often causing chronic inflammation, stiffness, and progressive loss of function.
“For many patients with knee osteoarthritis, there is a real treatment gap today,” said Florian Nima Fleckenstein, M.D., deputy head of Interventional Radiology Campus Mitte, Charité – Universitätsmedizin Berlin. “Conservative measures such as intra-articular injections no longer provide sufficient relief, but joint replacement is not an option for medical or personal reasons.”
GAE Addresses the Knee Osteoarthritis Treatment Gap
Genicular artery embolization (GAE) is a minimally invasive procedure that targets abnormal blood vessels surrounding the knee joint. In osteoarthritis, these vessels can accumulate around the joint and contribute to ongoing inflammation and pain. During the procedure, an interventional radiologist uses a thin catheter to reach the affected vessels and injects tiny particles that block blood flow, helping reduce inflammation and relieve pain without surgery.
The researchers proposed that GAE performed with rapidly resorbable gelatin-based microspheres could combine the advantages of both temporary embolic materials and permanent microspheres while avoiding some of their drawbacks. These specially designed spherical particles are calibrated by size and dissolve within hours.
“GAE is a whole new treatment regimen that targets abnormal hypervascularity around the joint and, in turn, modulates the pathological neurovascular environment,” Dr. Fleckenstein said. “By reducing both inflammation and pain, GAE with resorbable microspheres may be the first procedure that alters the course of the disease, slowing its progression.”
The prospective single-center study enrolled 194 patients with osteoarthritis-related knee pain, including 114 women and 80 men. All participants had failed to improve after at least three months of conservative treatment, including physical therapy, anti-inflammatory medications, and intra-articular injections. The median age was 69, and the median body mass index was 28.4.
Large Real-World Study Evaluates Resorbable Microspheres
“We believe these results carry real weight because they come from real-world data,” Dr. Fleckenstein said. “With this broad, inclusive study design, our participants are exactly the patients that physicians encounter every day in their practices.”
All participants underwent GAE using the resorbable microspheres between July and November 2024. Among them, 45 patients (23%) received two procedures to treat osteoarthritis in both knees, with the second treatment performed within four weeks of the first.
A total of 239 GAE procedures were completed under fluoroscopic imaging guidance. Every procedure was technically successful. No moderate or severe adverse events occurred, and only 6.7% of participants experienced mild, self-limiting reactions.
Researchers evaluated outcomes at baseline and again at six weeks, three months, six months, and 12 months after treatment. The six-month examination was conducted in person by an orthopedic surgeon. Follow-up rates remained high throughout the study, reaching 94% at six weeks (183/194), 89% at three months (172/194), 89% at six months (171/194), and 79% at 12 months (154/194).
Significant Pain Reduction and Functional Improvement
“In our cohort, we saw a significant drop in pain and a significant increase in function, including sports and recreation and daily activity,” Dr. Fleckenstein said. “Most importantly, their quality of life significantly increased.”
Pain levels improved rapidly and continued to improve over time. On the Numeric Rating Scale (a 0-to-10 measure of pain intensity), the median score decreased from 7 before treatment to 4 after six weeks and then to 3 at both the six-month and 12-month follow-ups, showing sustained improvement throughout the year.
Knee Injury and Osteoarthritis Outcome Score results also improved across every measured category over the 12-month period. Median daily activity scores rose from 53 to 71.5, while sports and recreation scores increased from 15 to 36. Symptom scores improved from 51 to 68, pain scores increased from 44 to 65 (where 0 indicates extreme knee pain and 100 indicates no pain at all), and quality-of-life scores increased from 19 to 40.
Previous research has established that a reduction of at least 2.0 points on the Numeric Rating Scale and an improvement of at least 10 points in Knee Injury and Osteoarthritis Outcome Score sub-scores represent a minimum clinically important difference.
Most Patients Achieve Clinically Meaningful Benefits
By the 12-month follow-up, 80% of participants had achieved improvements that exceeded the minimum clinically important difference according to their Numeric Rating Scale pain scores.
“Our study demonstrates that GAE using rapidly resorbable gelatin-based microspheres is a safe, minimally invasive therapy that provides meaningful pain relief and functional improvement in participants with osteoarthritis-related knee symptoms for at least 12 months,” Dr. Fleckenstein said. “By embolizing the pathological vessels, we’re able to normalize the vessel structure — and, in turn, the neuronal structure of the knee.”
Dr. Fleckenstein noted that this study, involving nearly 200 patients, represents the largest evidence base to date for GAE using rapidly resorbable microspheres.
“This lets us speak about safety and efficacy with real confidence,” he said. “For the right patient, it can mean lasting relief from a single, minimally invasive procedure — a meaningful new option between injections and joint replacement.”
Reference: “Genicular Artery Embolization Using Rapidly Resorbable Gelatin-based Microspheres for Osteoarthritis-related Knee Pain” by Florian Nima Fleckenstein, Dina David, Paolo Garducci, Tazio Maleitzke, Stephan Oehme, Lynn Jeanette Savic, Timo Alexander Auer, Bernhard Gebauer, Tobias Winkler and Federico Collettini, 16 June 2026, Radiology.
DOI: 10.1148/radiol.253312
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