Genicular artery embolization 'highly effective' in reducing knee OA pain
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Genicular artery embolization is safe and “highly effective” in reducing symptoms of moderate-to-severe knee osteoarthritis in patients who have been unresponsive to other conservative therapy, according to data.
“When we talk about the treatment options for knee OA, I think most of us are familiar two categories — either you do nothing and rest up your knee, or you can take medications such as Tylenol or ibuprofen — and that works for the majority of people, although it’s relatively temporary,” Siddharth A. Padia, MD, FSIR, a professor of radiology at UCLA and lead author of the study, said during a press briefing highlighting findings to be presented at the Society of Interventional Radiology 2021 Annual Scientific Meeting.
“When those stop working, many people will get joint injections — typically a steroid, such as cortisone, or a gel,” he added. “While those can work, they have relatively short-term results. A typical joint injection lasts from anywhere from 1 to 3 months, so it is not really built as a long-term solution. Currently, the only long-term solution is knee replacement, which does work, and it is recommended for people with severe, symptomatic OA, but the challenge with total knee replacement is that it does involve anesthesia, a hospital stay and a prolonged recovery and rehabilitation time.”
Genicular artery embolization, on the other hand, is a new procedure performed by interventional radiologists that reduces pain and other symptoms by decreasing inflammation. This is done by slowing down, or embolizing, the blood flow in parts of the knee, Padia said.
The outpatient procedure takes 2 hours to complete. It does not require general anesthesia, but instead uses conscious sedation through an IV and a numbing anesthetic at the fold of the knee. A small plastic catheter is then inserted into the blood vessel in the leg and guided via X-ray into the knee. Contrast dye is injected, and an angiogram is performed.
The resulting angiogram then allows providers to locate specific branches of the artery that are abnormally inflamed. A small amount of embolization particles is then injected into the area, reducing inflammation.
“It’s this inflammation in the knee joint that causes people’s pain and physical dysfunction,” Padia said. “So, in theory, if we can reduce the inflammation, we can actually make people’s pain go away and make their function overall improved.”
To analyze the safety and efficacy of this procedure in patients with symptomatic knee OA, Padia and colleagues conducted a prospective, single-center, open-label study. The researchers enrolled 40 adults aged 40 to 80 years with radiographic knee OA and moderate or severe knee pain, who had no prior knee surgery and were either not candidates for, or unwilling to receive, future surgeries. Participants were also required to have been unresponsive to conservative treatment, including NSAIDs or joint injections.
The researchers examined participants’ baseline pain through the visual analog scale and symptom scores via WOMAC. Genicular artery embolization was performed in all participants using 100 m particles (Embozene, Varian), injected into one to three arteries associated with the location of the patient’s pain. Padia and colleagues assessed adverse events and symptom scores at 1 week, 1 month, 3 months, 6 months and 1 year following the procedure.
According to Padia, technical success was achieved in 100% of participants. Among the patients, temporary skin discoloration and mild knee pain following the procedure were common and expected. Treatment-related adverse events included one participant with a groin hematoma requiring overnight observation, seven participants with self-resolving focal skin ulceration, and two patients with asymptomatic small bone infarction, identified through MRI, at 3 months.
At 12 months, WOMAC scores decreased 60% from a median of 52 to 21. Meanwhile, pain scores decreased 63% during the same time, from a median of 8/10 at baseline to 3/10. Among all participants, 67.5% experienced a greater than 50% reduction in WOMAC, while 70% demonstrated a greater than 50% reduction in pain scores.
“Based on the conclusions of this trial, we have the potential to completely disrupt and change the way patients with knee OA are treated,” Padia said. “So far, these results are very encouraging.”
Perspective
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Osteoarthritis (OA) of the knee is known to affect a significant portion of the population and is the most common joint to be affected by OA. As the population ages, the prevalence is expected to increase over the next several decades
Knee OA contributes to depression and in association with cardiovascular disease (CVD) and other factors leads to premature death and limited treatment options presently exist. Some currently recommended treatments, such as NSAIDs, need to be used with caution in older patients with comorbidities, such as CVD.
More recently, it has been recognized that OA pain and damage can be caused by inflammation. Genicular artery embolization (GAE) has shown preliminary benefit on managing symptoms by reducing blood flow to the lining of the knee that may be inflamed, thus reducing inflammation.
In this study evaluating the safety and efficacy of GAE for the management of knee osteoarthritis, patients were evaluated up to one year after treatment and beneficial outcomes were seen as early as 3 days after the procedure with a greater than 50% reduction in the average pain scores. In addition, 70% of patients continued to report more than a 50% reduction in pain scores one-year at follow-up.
For patients suffering with knee OA who are not candidates or who do not wish to have knee surgery, additional safe and effective therapeutic options are needed, and this study shows significant promise for the utilization of GAE as a treatment modality for our patients.
Additional prospective randomized trials assessing who will benefit the most from these treatments, how long the pain reduction will last, long-term side effects, and if treatment has any impact on preventing progression should be done; however, given the present low risk and high potential for benefit, this procedure should be considered in select patients if available.
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Padia S. Abstract 16. Presented at Society of Interventional Radiology Annual Scientific Meeting; March 16, 2021. (virtual meeting).
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