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

  • RFA often starts with a test nerve block. In one trial, people needed at least a 50% drop in pain from the test block to have RFA2.
  • In that trial of 151 people, 74% had at least 50% less pain 6 months after cooled RFA, compared with 16% after a steroid injection. People knew which treatment they got2.
  • For GAE, sham-controlled trials are mixed3.
  • A trial comparing GAE with nerve ablation, called GENI, has not reported results yet1.
  • Evidence status as of October 2026: head-to-head data are limited.

How each works

GAE. An interventional radiologist passes a small catheter through an artery to the small arteries around the knee. Tiny particles slow blood flow to extra vessels in the inflamed joint lining. The goal is to calm the inflammation and ease pain1,4.

RFA. A doctor places thin needles near small nerves around the knee, using X-ray pictures to guide them, and heats the nerves with radiofrequency energy. The goal is to stop those nerves from sending pain signals2.

The test nerve block. Before RFA, the doctor often numbs the same nerves with a small injection of numbing medicine. If your pain drops enough, the doctor may offer RFA. In one trial, people needed at least a 50% drop in pain from the test block to have RFA2.

Questions to ask

  • Would you start with a test nerve block for me?
  • Which doctors do each procedure where I live?
  • Is one of these a better fit for my knee, and why?

What the evidence shows

RFA. In a randomized trial of 151 people with knee pain for 6 months or more, 74% had at least 50% less pain 6 months after cooled RFA, compared with 16% after a steroid injection2. People knew which treatment they got, and several authors were on the device maker's advisory board2. An arthritis guideline recommends RFA for knee arthritis conditionally5, and an orthopedic guideline says nerve treatments "may reduce pain and improve function," with limited evidence6.

GAE. Sham-controlled trials are mixed. One small trial found less pain after GAE than after a sham procedure, and two larger trials found no clear difference3. Read what GAE studies show.

Head to head. Head-to-head data are limited. A trial comparing GAE with nerve ablation, called GENI, has not reported results yet1. A 2024 study used a cost-effectiveness model built on earlier trials. In that model, RFA showed a larger effect on pain than GAE, mostly in the short term, but GAE was more likely to be cost-effective7. A model is not a trial, and its results depend on its assumptions.

Two GAE trials still underway, MOTION and RESORB, compare GAE with a steroid injection8,9, the same comparison used in the RFA trial above.

Side effects to ask about

GAE. In one review, skin color change over the knee happened in about 16 in 100 people and short-term knee pain in about 10 in 10010. A small skin sore is rare, about 3 in 1,0001. Read about GAE side effects and recovery.

RFA. In the RFA trial, there were no procedure-related serious adverse events2. Ask about numbness or skin changes near the needle sites, and about bleeding or infection.

Questions to ask

  • What side effects do your patients have most often with each procedure?
  • What should I watch for at home afterward?

How long relief may last, and repeat treatments

RFA. The RFA trial reported results at 6 months2. Ask how long relief usually lasts, and whether RFA can be repeated if pain comes back.

GAE. Long-term GAE data come mostly from studies without a comparison group11,12. A repeat GAE may be considered after about 12 months, but it has not been well studied4.

Coverage differences

Coverage for both depends on your plan. Medicare has no coverage policy written specifically for GAE13, and some commercial insurers call GAE investigational14,15. Ask your plan about RFA separately, because rules for the two procedures can differ. Read about GAE insurance and Medicare coverage.

Common questions

Is GAE or RFA better for knee pain?

A trial comparing them directly has not reported results yet1. RFA has a randomized trial against steroid injections2, and sham-controlled GAE trials are mixed3. Ask your doctor how each fits your knee and your goals.

What is a genicular nerve block?

It is a small injection of numbing medicine near the nerves around the knee. It is often used as a test before RFA. In one trial, people needed at least a 50% drop in pain from the block to have RFA2.

Is RFA surgery?

No. RFA is done through thin needles placed near the knee nerves with X-ray guidance. In the trial, people went home after the procedure2.

Do guidelines recommend RFA for knee arthritis?

An arthritis guideline recommends it conditionally5, and an orthopedic guideline says nerve treatments may reduce pain and improve function, with limited evidence6.

Does insurance cover GAE or RFA?

Coverage varies by plan and by procedure. Medicare has no coverage policy written specifically for GAE13. Ask your plan about each procedure separately.

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. Ahmed et al., Society of Interventional Radiology position statement on genicular artery embolization, Journal of Vascular and Interventional Radiology 2026 (PMID 42118083) ↩︎
  2. Davis et al., randomized trial of cooled radiofrequency ablation versus steroid injection for knee osteoarthritis pain, Regional Anesthesia & Pain Medicine 2018 (PMID 29095245) ↩︎
  3. Milhem et al., systematic review of sham-controlled trials of GAE, Journal of Orthopaedics 2025 (PMID 40766107) ↩︎
  4. Brown et al., genicular artery embolization: a technical review, Journal of Clinical Medicine 2025 (PMID 40142914) ↩︎
  5. Kolasinski et al., 2019 American College of Rheumatology/Arthritis Foundation osteoarthritis guideline, Arthritis Care & Research 2020 (PMID 31908149) ↩︎
  6. American Academy of Orthopaedic Surgeons, management of osteoarthritis of the knee (non-arthroplasty), 3rd edition, 2021 ↩︎
  7. Kwak et al., cost-effectiveness model comparing GAE, radiofrequency ablation, and steroid injection, American Journal of Roentgenology 2024 (PMID 39320355) ↩︎
  8. ClinicalTrials.gov, MOTION randomized trial of GAE versus steroid injection (NCT05818150) ↩︎
  9. ClinicalTrials.gov, RESORB randomized trial of GAE versus steroid injection (NCT06872567) ↩︎
  10. Ashraf et al., systematic review of GAE safety and results, 2025 (PMID 40219609) ↩︎
  11. Okuno et al., midterm results after embolization for knee osteoarthritis, Journal of Vascular and Interventional Radiology 2017 (PMID 28365171) ↩︎
  12. Little et al., GENESIS long-term results, CardioVascular and Interventional Radiology 2024 (PMID 38819473) ↩︎
  13. CMS, Medicare Coverage Database (searched October 2026) ↩︎
  14. Blue Cross and Blue Shield of Texas, medical policy SUR705.048, effective July 15, 2025 ↩︎
  15. Molina Clinical Policy No. 410, genicular artery embolization of the knee for osteoarthritis ↩︎