Get urgent care for a knee that is suddenly hot, red, or very swollen, a fever, not being able to put weight on your leg, or calf swelling or shortness of breath.

Key facts

  • Only one of these three trials, GENESIS II, compares GAE with a sham procedure2.
  • MOTION and RESORB compare GAE with a steroid injection into the knee, and people know which treatment they got1,3.
  • As of October 2026, MOTION is no longer recruiting, GENESIS II lists one site in the UK, and RESORB lists one site in the US1,2,3.
  • A trial is research. Chance decides your group, so you might get the comparison treatment instead of GAE1,2,3.

Why these trials matter

Sham-controlled trials of GAE are mixed so far. Of three trials, one small trial favored GAE and two larger ones found no clear difference4. Knee arthritis pain goes up and down, and expecting a treatment to help can ease pain on its own. New trials aim to show how much of the relief comes from GAE itself.

The Society of Interventional Radiology (SIR) says ongoing randomized trials aim to measure possible placebo effects5. Read what studies show so far for the results to date.

What a sham-controlled trial is

In a sham-controlled trial, some people get GAE and others get a sham (fake) procedure, and they are not told which one they got. If the GAE group does better, the difference is more likely to come from GAE itself and not from the placebo effect.

In a double-blind trial, neither the people taking part nor the people measuring the results know who got which procedure. GENESIS II is double-blind2.

A trial that compares GAE with a steroid injection asks a different question: does GAE do better than a treatment people already use? In MOTION and RESORB, people know which treatment they got1,3.

The three trials

These are the randomized trials named on ClinicalTrials.gov and in the SIR statement. Listings change, so check each record for the latest status.

Randomized trials of GAE for knee arthritis, as listed on ClinicalTrials.gov in October 2026
TrialWhat it comparesWho it is forSize and status
MOTION (NCT05818150) GAE or a steroid injection. People know which treatment they got. Adults 21 or older with knee pain for at least 90 days despite other care, and arthritis of any grade on X-ray. About 264 people at 27 sites in 6 countries. Active, no longer recruiting1.
GENESIS II (NCT05423587) GAE or a sham procedure, in a double-blind trial. Adults 45 or older with mild to moderate arthritis on X-ray (grades 1 to 3) and pain for at least 3 months despite other care. About 110 people at one site in the UK. Listed as recruiting, but the listing was last checked in November 20242. SIR says enrollment is complete5.
RESORB (NCT06872567) GAE or a steroid injection. People know which treatment they got. Adults 40 or older with pain in one area of the knee who can have a procedure through an artery. About 126 people, with one US site listed. Recruiting3.

Who can take part

Each trial has its own rules. In these listings, common ones are a minimum age, a grade of arthritis on X-ray, and knee pain that has not improved with other care for at least 3 months1,2. People with rheumatoid arthritis or a joint infection are left out of MOTION and GENESIS II, and MOTION leaves out a knee that has already been replaced1,2.

GENESIS II also needs people who can have an MRI and lie flat for several hours2. The study team checks your records and may order X-rays, scans or blood tests before you can join.

Questions to ask

  • Do I meet the rules for any GAE trial?
  • What tests would I need before I could join?
  • Is there a trial that includes people with my grade of arthritis?

How to find a trial site

You can search registered GAE trials on ClinicalTrials.gov6. Each listing shows whether it is recruiting, where its sites are, and who to contact. Listings can be out of date, so call the study contact to confirm.

Your own doctor or an interventional radiologist can help you read a listing and decide whether a trial fits. Bring the trial number, such as NCT05818150, to the visit.

Costs and insurance in a trial

Medicare has approved coverage of routine costs in some GAE device studies (for example MOTION, NCT05818150)7. Ask the study team what the trial pays for, what your insurance pays for, and what you would pay. Read GAE insurance and Medicare coverage for more.

Questions to ask before you join

A trial is a choice, not a requirement. You can say no, and you can usually leave a trial later. Ask the study team these questions before you sign anything.

Questions to ask

  • What does each group get, and how is my group chosen?
  • If I am in the sham or steroid group, can I have GAE later?
  • How long will I be followed, and how many visits are there?
  • What are the risks of the procedure and of the tests?
  • Who pays for the procedure, the visits and any travel?
  • What happens to my usual care if I join or leave?

Common questions

Are there clinical trials for GAE?

Yes. Randomized trials comparing GAE with sham procedures or steroid injections are still underway (for example MOTION, GENESIS II, RESORB)1,2,3.

What is a sham-controlled trial?

Some people get GAE and others get a sham (fake) procedure, and they are not told which one they got. It helps show how much of any relief comes from GAE itself.

Can I join a GAE trial?

It depends on each trial’s rules and on whether it is still enrolling. As of October 2026, MOTION is no longer recruiting, and RESORB lists one US site that is recruiting1,3. Check ClinicalTrials.gov and ask your doctor.

Will I definitely get GAE in a trial?

No. In a randomized trial, chance decides your group. You might get a sham procedure or a steroid injection instead of GAE2,1.

Does Medicare pay for GAE in a trial?

Medicare has approved coverage of routine costs in some GAE device studies (for example MOTION, NCT05818150)7. Ask the study team what you would pay.

Bring questions to your visit

A printable list of questions about GAE, with background notes from the sources. Talk with your doctor about these questions.

Questions to ask before GAE

Talk with your doctor before you decide. This information does not replace personal medical advice. Read the medical disclaimer.

Sources

  1. ClinicalTrials.gov, MOTION randomized trial of GAE versus steroid injection (NCT05818150) ↩︎
  2. ClinicalTrials.gov, GENESIS II sham-controlled trial of GAE (NCT05423587) ↩︎
  3. ClinicalTrials.gov, RESORB randomized trial of GAE versus steroid injection (NCT06872567) ↩︎
  4. Milhem et al., systematic review of sham-controlled trials of GAE, Journal of Orthopaedics 2025 (PMID 40766107) ↩︎
  5. Ahmed et al., Society of Interventional Radiology position statement on genicular artery embolization, Journal of Vascular and Interventional Radiology 2026 (PMID 42118083) ↩︎
  6. ClinicalTrials.gov, registered trials of genicular artery embolization for knee osteoarthritis ↩︎
  7. CMS, approved investigational device exemption (IDE) studies ↩︎