A genicular nerve block is an injection of local anesthetic, sometimes combined with a steroid, around the small nerves that carry pain signals from your knee joint to your brain. By temporarily numbing these nerves, the procedure can provide significant relief from chronic knee pain, particularly when other treatments like physical therapy, anti-inflammatory medications, or steroid injections into the joint itself haven’t worked. It’s also used before knee surgery to help manage post-operative pain.
Which Nerves Are Targeted
Four small nerve branches, called genicular nerves, wrap around the bones of your knee. Each one runs along the surface of the bone alongside a small artery. The block typically targets three of these four branches: the superior medial genicular nerve (on the inner side of the knee, above the joint), the superior lateral genicular nerve (on the outer side, above the joint), and the inferior medial genicular nerve (on the inner side, below the joint). These three carry the majority of pain signals from the knee capsule and surrounding tissue.
Because each nerve sits in a predictable spot near a bony landmark, the provider can locate them reliably using either ultrasound or fluoroscopy (a type of live X-ray). This anatomical consistency is what makes the block technically straightforward compared to some other nerve procedures.
Who Benefits Most
The most common candidate is someone with chronic knee pain from osteoarthritis who has already tried and failed first-line treatments: physical therapy, oral pain relievers, and steroid injections directly into the joint. A genicular nerve block offers a minimally invasive, non-surgical option that sits between those conservative measures and a total knee replacement.
This can be especially valuable if knee replacement surgery isn’t an option for you. Some people are poor surgical candidates because of a high BMI, heart or lung conditions, or other health factors that make major surgery risky. Others simply prefer to avoid or delay surgery. In a case series published in Orthopedic Reviews, six patients with chronic knee osteoarthritis who had failed conventional treatments, including joint injections, found significant relief with genicular nerve blocks.
The block is also used in a surgical context: an anesthesiologist may perform it before a total knee replacement to reduce the severity of pain you experience during recovery.
What Happens During the Procedure
You’ll lie on your back with your knee exposed. The provider cleans the skin with an antiseptic and may use a small amount of lidocaine to numb the skin at each injection site. Using ultrasound or fluoroscopy for guidance, they then advance a thin needle toward each of the three target nerves.
At each nerve, about 3 mL of anesthetic is injected, for a total of roughly 9 mL across all three sites. The anesthetic is typically a long-acting agent like bupivacaine or ropivacaine. When the goal is longer-lasting relief rather than just a diagnostic test, a corticosteroid is often mixed into the injection. The entire procedure takes around 15 to 30 minutes and is done in an outpatient setting.
Diagnostic Block vs. Therapeutic Block
Genicular nerve blocks serve two distinct purposes, and this is an important distinction to understand if your provider recommends one.
A diagnostic block uses only local anesthetic with no steroid. The goal is to see whether numbing these specific nerves relieves your pain. If your pain drops by 50% or more after the injection, that confirms the genicular nerves are the primary pathway for your knee pain. This information matters because it predicts whether a longer-lasting procedure, called radiofrequency ablation, will work for you. In one study, patients’ average pain score dropped from 8.5 out of 10 to 2.2 after a diagnostic block, confirming the nerves as the pain source.
A therapeutic block includes a corticosteroid alongside the anesthetic. The steroid reduces inflammation around the nerve and can extend pain relief well beyond the few hours that the anesthetic alone would provide. Among studies comparing therapeutic blocks (with steroid) to radiofrequency ablation, three out of five found the two approaches provided comparable pain relief.
How Long Relief Lasts
The anesthetic component wears off within several hours. If your block included a steroid, meaningful pain relief can last weeks to a few months, though this varies considerably from person to person. A diagnostic block without steroid provides only temporary relief, lasting the duration of the anesthetic’s effect.
Because the nerves are not permanently damaged by the injection, the pain will eventually return. This is by design for a diagnostic block, and it’s the expected limitation of a therapeutic one. Repeat blocks are possible, but if the relief consistently fades, your provider may discuss radiofrequency ablation as a next step.
Radiofrequency Ablation as a Next Step
If a diagnostic genicular nerve block confirms your pain responds well, the next option is typically genicular nerve radiofrequency ablation. This procedure uses heat to create a more lasting disruption of those same nerves. Several techniques exist, including conventional, cooled, and pulsed radiofrequency.
A systematic review comparing the two approaches found that ablation produces more substantial and longer-lasting pain relief than a diagnostic block with anesthetic alone. At one month and three months, patients who received radiofrequency ablation reported significantly less knee pain than those who received a block. Cooled radiofrequency ablation, which uses a generator set to 60°C while tissue temperatures exceed 80°C, creates a larger treatment zone around the nerve and was used in multiple studies with positive results.
The comparison between ablation and therapeutic blocks (with steroid) is less clear-cut. Current evidence is limited, and some studies show similar outcomes between the two. Your provider will weigh factors like how long your therapeutic blocks last, your overall health, and your preferences when recommending one approach over the other.
Risks and What to Expect Afterward
Genicular nerve blocks are considered low-risk. The nerves targeted are purely sensory, meaning they carry pain signals but don’t control muscle movement. Numbing or even ablating them won’t cause weakness in your leg or change how your knee functions mechanically.
The most common side effects are minor: soreness, bruising, or swelling at the injection sites. Because each genicular nerve runs alongside a small artery, there is a slight risk of inadvertent vascular puncture, though ultrasound or fluoroscopic guidance minimizes this. Infection at the injection site is possible but rare with proper sterile technique. Some people experience temporary numbness in the skin around the knee, which resolves as the anesthetic wears off.
Most people can bear weight and walk immediately after the procedure. You may be asked to avoid strenuous activity for a day or two. It’s common to feel the full benefit of a therapeutic block within the first week as the steroid takes effect.