Radiofrequency ablation (RFA) uses heat to switch off the small nerves that carry pain from a joint. When it works, relief usually lasts about 6 to 12 MONTHS, sometimes longer, until the nerve grows back. Then it can be repeated.
It only suits some people. You’ll have a test block first: a numbing injection next to the nerve. If that takes most of your pain away for a few hours, RFA has a better chance of helping.
The evidence is moderate at best.
For back pain from the small spinal joints, trials disagree on how much it helps. For knee arthritis, results look more encouraging, and US rheumatologists’ latest guidance supports it for some people.
What RFA is used for
- Facet joint pain in the back or neck: the facet joints are small joints at the back of the spine. RFA targets the tiny nerves that supply them (the medial branch nerves). It’s for pain in the back or neck itself
- Knee arthritis pain: RFA targets the genicular nerves around the knee. It’s an option for people who can’t have, or want to put off, a knee replacement. It’s sometimes used for pain that lingers after a replacement too
- SI joint pain: used less often, and the evidence is weaker. See SI joint pain
- Not for sciatica: RFA doesn’t treat leg pain from a pinched nerve. That needs a different approach. See epidural steroid injection
The test block comes first
- What it is: local anesthetic is injected next to the nerves that would be treated. If your usual pain mostly disappears for a few hours, those nerves are likely carrying it
- For the back: many US insurers, including Medicare, want two separate test blocks, each easing your usual pain by at least 80%
- Keep notes: in the hours after the block, try the movements that normally hurt and write down how much pain you have
- If the block does nothing: RFA is unlikely to help, and the pain is probably coming from somewhere else
What happens on the day
- The needle: the skin is numbed, and a thin needle is guided to each nerve using X-ray or ultrasound
- The heat: radio waves heat the needle tip, which damages the nerve so it stops sending pain signals
- Home the same day: most people rest that day and are back to normal activities within a day or two
- Relief isn’t always instant: some people feel better straight away. For others it takes up to about 3 weeks
How long RFA lasts, and repeats
- Typical relief: about 6 to 12 months. For some people it lasts a few years
- Why it wears off: the nerve slowly grows back, and the pain can return with it
- For the knee: in studies, about 1 in 2 people had their pain at least halved at six months. By a year, it was closer to 4 in 10
- Repeats: it can be done again if it helped the first time. For the back, Medicare covers a repeat only if the last one gave at least 50% relief for at least 6 months, and no more than twice a year for the same area
What the evidence says
- Back pain: for facet joint pain, some trials against a fake procedure show modest short-term relief. Long-term benefit is unclear, and reviews rate the evidence as low to moderate quality
- Knee arthritis: newer techniques that treat a larger area of nerve show more consistent results. Reviews rate this evidence as moderate
- Choosing the right person matters: results are better when the test block clearly worked
RFA turns the pain signal down. It doesn’t fix the joint, so the joint still needs strength.
Side effects
- Soreness at the site: common, often with a burning feeling, for 1 to 2 weeks
- Bruising: where the needle went in
- Rare but serious: infection, bleeding, or lasting nerve damage
- Before the day: tell your doctor if you take blood thinners
The Cleveland Clinic guide to radiofrequency ablation covers the procedure step by step if you want more detail.
Use the relief window
- Start exercise while the pain is down: this is the time to build back, hip and thigh strength you couldn’t build before
- Build up gradually: the pain signal is quieter, but the joint hasn’t changed. Increase load week by week
- For the back: see degenerative disc disease for how to keep a worn spine moving
- For the knee: see knee arthritis
Go to the emergency department now if
- New trouble peeing, or leaking pee or poo without knowing, after a spine procedure
- Numbness around your genitals, buttocks or inner thighs
- New weakness in your leg or legs that is getting worse
Call your doctor today if
- The needle sites get redder, hotter or more swollen after the first couple of days
- You have a fever or chills, or feel unwell
- Your knee becomes hot, very swollen and painful after knee RFA
Get it checked if
- Burning or soreness lasts beyond about 2 to 3 weeks
- You’ve had no change in your usual pain after a month
- Your pain changes in type, such as new leg pain or pins and needles
- You’re being offered repeats even though the last one didn’t help
RFA can buy you months of quieter pain. What you build in those months decides what happens next.