In short — A genicular nerve block uses a numbing injection near the small sensory nerves around the knee to test whether those nerves are carrying a meaningful part of the knee's arthritis pain. If the block gives clear, temporary relief, radiofrequency ablation of the same nerves may offer longer-lasting relief in selected patients whose knee osteoarthritis has not responded enough to conservative care.
A patient in Orange Park has walked with a cane for two years, ever since a knee X-ray came back reading "severe degenerative changes." Physical therapy helped a little. Two rounds of cortisone injections helped for a few weeks each time. A knee replacement is still years away, by the surgeon's own estimate, and in the meantime the pain has not gotten any easier to live with.
Another patient in Mandarin has a mild-looking knee X-ray, barely enough arthritis to mention, yet the pain climbing stairs is real and constant. Told repeatedly that "it's not that bad," the frustration is less about the pain itself and more about not being believed.
Both situations point to the same gap in typical knee osteoarthritis care: between "keep doing physical therapy" and "you'll eventually need a knee replacement," there is a middle step that targets the nerves carrying the pain signal itself, rather than the joint or the inflammation directly.
What a genicular nerve block and RFA actually are
The knee joint is supplied by several small sensory nerves, called genicular nerves, that carry pain signals from the joint back toward the spinal cord. A genicular nerve block places numbing medication near these nerves, under image guidance, without entering the joint space itself.
If the block produces clear, though temporary, relief, it suggests these nerves are carrying a meaningful part of the knee's pain signal. That result is what makes a patient a reasonable candidate for genicular nerve radiofrequency ablation (RFA), a procedure that uses heat generated by radiofrequency energy to interrupt those same nerves for a longer period, generally many months.
A common point of confusion: why doesn't the X-ray settle it?
Patients often assume that how "bad" an X-ray looks should predict how much a knee hurts, in either direction. In practice, the correlation between X-ray severity and reported pain is inconsistent: some patients with severe-appearing arthritis have modest pain, and some with mild-appearing changes have significant pain.
This is not a sign that anyone is exaggerating or that imaging is useless. It simply means an X-ray shows structural change, not pain itself, and a genicular nerve block is one way to test whether the nerves supplying a specific knee are, in fact, a meaningful source of that individual patient's pain, regardless of what the X-ray alone suggests.
Who may be a candidate
Genicular nerve block and RFA are generally considered for knee osteoarthritis pain that has not improved enough with conservative measures such as physical therapy, weight management, activity modification, bracing, and oral or intra-articular medication. They are often discussed with patients who are not yet ready for, or are not good candidates for, knee replacement surgery — see the arthritis care overview for how a joint-replacement evaluation fits into the broader picture.
Not every patient with knee osteoarthritis needs, or is an appropriate candidate for, this approach. Diagnosis, exam findings, prior treatment, and how a patient responds to the diagnostic block all factor into whether RFA makes sense, and this decision is made after a full evaluation rather than from imaging alone.
What happens during the procedure
The diagnostic genicular nerve block comes first. Using X-ray or ultrasound guidance, numbing medication is injected near several genicular nerves around the knee. Meaningful relief over the following hours is what supports moving forward with RFA; if the block does not help enough, RFA is not typically pursued, and other options are reconsidered instead.
When the block response supports it, radiofrequency ablation targets the same nerves with a needle-based probe positioned under image guidance, using heat to interrupt the nerve's ability to carry pain signals. The procedure is done under local anesthesia, usually as an outpatient visit lasting well under an hour.
What this means for patients
Knee osteoarthritis pain that has plateaued despite therapy, weight management, and injections is worth discussing with a physician who can test the nerve pathway directly, rather than assuming the only choices left are living with it or waiting for knee replacement. The diagnostic block exists specifically so a patient and physician can see a real response before deciding whether RFA is a reasonable next step.
When RFA does help, relief is generally not immediate; it typically develops over one to three weeks as the treated nerves settle, and most patients resume normal activity within a few days of the procedure itself. Because genicular nerves can regrow, relief is not considered permanent, and RFA can sometimes be repeated if a response fades and the original diagnostic block logic still applies.
Risks and recovery
Possible risks include temporary soreness or bruising at the injection sites, infection, bleeding, and a small area of temporary skin numbness near the knee. Some patients do not get meaningful relief even after a promising diagnostic block, and RFA is not a substitute for addressing mechanical problems within the joint itself, such as a torn meniscus, that may need a different evaluation.
Seek prompt medical attention for fever, spreading redness or warmth around the knee, significant new swelling, or an inability to bear weight that is out of proportion to your usual arthritis pain.
This article is for general educational purposes only and is not a substitute for a medical evaluation. It does not diagnose any individual's knee pain or guarantee any particular outcome from treatment. Seek prompt medical care for signs of infection or new, severe symptoms that concern you.
The bottom line
Knee osteoarthritis pain that persists despite conservative care does not automatically mean a knee replacement is the only remaining option, nor does a mild-looking X-ray mean the pain isn't real. A genicular nerve block offers a way to test, directly, whether the nerves supplying the knee are carrying a meaningful share of the pain signal, and radiofrequency ablation may offer longer-lasting relief for selected patients whose diagnostic block responded well.
A careful evaluation can help sort out whether this approach fits a given patient's diagnosis, prior treatment, and goals.
Frequently Asked Questions
What is a genicular nerve block?
A genicular nerve block is a diagnostic injection that places numbing medication near several small sensory nerves around the knee joint. If it provides clear, temporary relief, it suggests those nerves are carrying a meaningful part of the knee's pain signal, which helps identify candidates for a longer-acting nerve treatment.
How is a genicular nerve block different from a corticosteroid or gel injection into the knee?
A corticosteroid or viscosupplementation (gel) injection goes inside the joint space itself to reduce inflammation or add lubrication. A genicular nerve block does not enter the joint at all; it targets the sensory nerves just outside the joint that carry pain signals from it, mainly to test whether those nerves are a meaningful pain source before considering radiofrequency ablation.
What happens during genicular nerve radiofrequency ablation (RFA)?
Under image guidance, a needle is positioned next to each targeted genicular nerve and heat generated by radiofrequency energy is used to interrupt the nerve's ability to carry pain signals for a period of time. It is typically performed only after a diagnostic genicular nerve block has already shown meaningful, though temporary, relief.
Who might be a candidate for a genicular nerve block or RFA?
Genicular nerve block and RFA are generally considered for knee osteoarthritis pain that has not improved enough with conservative measures such as physical therapy, weight management, activity modification, and oral or intra-articular medication, particularly in patients who are not yet ready for or are not candidates for knee replacement.
What are the risks of genicular nerve block and RFA?
Possible risks include temporary soreness or bruising at the injection sites, infection, bleeding, temporary numbness in a small area of skin near the knee, and inadequate or incomplete relief. Nerves can regrow over time, so relief from RFA is generally not considered permanent.
Related patient education
- What Patients Should Know Before Considering PRP, MFAT, or SVF Injections
- Radiofrequency Ablation for Back or Neck Pain: What It Can and Cannot Do
- What Patients With Back or Neck Pain Wish Someone Had Explained About MRI Results
- Preparing for an interventional pain procedure
Related services
Has knee arthritis pain stopped responding to conservative care?
A careful evaluation can help determine whether a genicular nerve block and RFA fit your diagnosis, history, and goals.
Contact the office about an appointment