Nerve Blocks & Radiofrequency Ablation

What Are Nerve Blocks for Joint Pain?

Nerve blocks are procedures that interrupt pain signals traveling from a joint to the brain. For chronic joint pain, particularly in the knee, the most common approach targets the genicular nerves — a set of small nerves that carry pain signals from the knee joint.

There are two main types of nerve block procedures used for joint pain:

• Diagnostic nerve blocks: Temporary injections of local anesthetic to confirm which nerves are causing your pain
• Radiofrequency ablation (RFA): A longer-lasting treatment that uses heat generated by radio waves to disrupt the nerves carrying pain signals

These procedures are typically considered when other treatments, such as physical therapy, medications, and injections (cortisone or hyaluronic acid), have not provided adequate relief, and the patient wants to avoid or delay joint replacement surgery.

How Genicular Nerve Blocks Work

The Genicular Nerves

The knee joint is supplied by several genicular nerves, which are branches of larger nerves in the leg. The three most commonly targeted nerves are:

• Superior medial genicular nerve (inside upper knee)
• Superior lateral genicular nerve (outside upper knee)
• Inferior medial genicular nerve (inside lower knee)

These nerves carry pain signals from the knee joint but do not control muscle movement. This means they can be safely blocked or ablated without affecting your ability to walk or move your leg.

The Diagnostic Block

Before radiofrequency ablation, your provider will perform one or two diagnostic nerve blocks:

1. Imaging guidance: Using fluoroscopy (live X-ray) or ultrasound, the provider identifies the exact location of the genicular nerves
2. Local anesthetic injection: A small amount of numbing medication is injected near each target nerve
3. Pain assessment: You are asked to rate your pain before and after the block
4. Success criteria: If your pain decreases by 50% or more, you are considered a good candidate for RFA

Medicare and most insurers require at least one, and often two, successful diagnostic blocks before approving radiofrequency ablation.

Radiofrequency Ablation (RFA)

How RFA Works

Radiofrequency ablation uses a specialized needle with an electrode tip to create targeted heat near the genicular nerves:

1. Imaging guidance: Fluoroscopy or ultrasound is used to position the needle precisely
2. Sensory testing: A small electrical current is applied to confirm the needle is near the correct nerve (you may feel tingling or pressure, but not muscle contraction)
3. Local anesthetic: The area is numbed before ablation begins
4. Heat application: Radiofrequency energy heats the needle tip to approximately 80 degrees Celsius (176 degrees Fahrenheit) for 60-90 seconds
5. Nerve disruption: The heat creates a small lesion that interrupts the nerve’s ability to transmit pain signals

Types of RFA

• Conventional (thermal) RFA: Standard heat-based ablation, most commonly used and most studied
• Cooled RFA: Uses water-cooled electrodes to create larger lesions, potentially improving success rates
• Pulsed RFA: Uses intermittent energy pulses at lower temperatures, considered less destructive but possibly less effective

Recovery After RFA

• Day of procedure: You can go home the same day; someone should drive you
• First 1-2 weeks: Mild soreness or increased pain at the treatment sites is normal
• 2-3 weeks: Most patients begin to notice meaningful pain relief
• Full effect: Maximum pain relief is typically reached within 2-4 weeks
• Activity: Normal activities can usually resume within a few days; strenuous activity should wait 1-2 weeks

What the Evidence Shows

Research Findings

Moderate evidence supports genicular nerve procedures for chronic knee pain:

• Pain reduction: Multiple studies report 50-70% pain improvement in patients who respond to the treatment
• Duration: Pain relief typically lasts 6-12 months, with some patients experiencing relief for over a year
• Function improvement: Patients often report improved ability to walk, climb stairs, and perform daily activities
• Patient satisfaction: Studies consistently show high satisfaction rates among patients who had successful diagnostic blocks before RFA

Who Benefits Most

Research indicates the best outcomes occur in patients who:

• Had at least 50% pain relief from diagnostic nerve blocks
• Have moderate to severe osteoarthritis (not mild arthritis)
• Have failed other conservative treatments
• Are not immediate candidates for joint replacement, or wish to delay surgery

Limitations

• Temporary relief: Nerves can regenerate over time, so pain may return after 6-12 months
• Repeat procedures: RFA can be repeated when pain returns, but long-term data on repeated procedures is limited
• Not for everyone: About 20-30% of patients do not experience significant relief even after successful diagnostic blocks

Who Is a Candidate?

Good Candidates

You may be a candidate for genicular nerve blocks and RFA if you:

• Have chronic knee pain from osteoarthritis lasting more than 3 months
• Have tried and failed conservative treatments (physical therapy, medications, injections)
• Cannot or do not want to undergo joint replacement surgery
• Are medically fit for a minor outpatient procedure
• Have had a positive response to diagnostic nerve blocks

Not Recommended For

Nerve blocks and RFA may not be appropriate if you:

• Have mild arthritis that can be managed with conservative treatments
• Have an active joint infection
• Take blood thinners that cannot be safely paused
• Have a bleeding disorder
• Have a pacemaker (certain RFA types may interfere — discuss with your doctor)
• Are a good candidate for joint replacement and prefer a definitive solution

Hip Joint Nerve Blocks

While genicular nerve blocks for the knee are more widely studied, similar procedures exist for hip pain:

• Target nerves: The obturator nerve, femoral nerve branches, and accessory obturator nerve supply the hip joint
• Evidence: Growing but less robust than for knee procedures
• Technique: Typically performed under fluoroscopic or ultrasound guidance
• Results: Early studies show promising pain reduction in hip osteoarthritis patients

The Procedure: Step by Step

Before Your Procedure

• Medical review: Your provider reviews your medications, allergies, and medical history
• Blood thinners: You may need to stop certain medications 3-7 days before the procedure (follow your doctor’s instructions)
• Eating and drinking: You may be asked to limit food intake before the procedure if sedation is planned
• Arrange a ride: You will need someone to drive you home

During the Procedure

1. You lie face-up on a procedure table
2. The treatment area is cleaned and draped
3. Local anesthetic numbs the skin
4. Under imaging guidance, needles are positioned near each target nerve
5. Sensory testing confirms correct placement
6. Additional local anesthetic is injected for comfort
7. Radiofrequency energy is applied for 60-90 seconds per nerve
8. Needles are removed and small bandages are applied

Total time: 30-60 minutes

After Your Procedure

• Rest in a recovery area for about 30-60 minutes
• You can typically resume normal activities the next day
• Apply ice to the treatment area if sore
• Avoid strenuous activity for 1-2 weeks
• Keep follow-up appointments to assess your response

Cost and Insurance Coverage

Medicare Coverage

Medicare may cover genicular nerve blocks and RFA under Part B:

• Coverage requirements: Documentation of failed conservative treatments and successful diagnostic blocks
• Regional variation: Coverage is determined by your Medicare Administrative Contractor (MAC), and policies vary by region
• Cost to you: After the annual deductible, you typically pay 20% of the Medicare-approved amount
• Important note: Some MACs have proposed changes to coverage policies for genicular nerve procedures. Check with your provider about current local coverage determinations (LCDs)

Private Insurance

Most private insurers cover nerve blocks and RFA:

• Prior authorization is usually required
• Documentation needed: Failed conservative treatments, positive diagnostic blocks
• Out-of-pocket costs depend on your plan’s deductible, copay, and coinsurance

Without Insurance

• Diagnostic nerve block: $1,000-$2,000 per procedure
• Radiofrequency ablation: $2,000-$5,000 per procedure
• Total cost for diagnostic + RFA: $3,000-$7,000 or more

Frequently Asked Questions

How long does pain relief last after RFA?

Most patients experience pain relief lasting 6-12 months. Some patients report relief for over a year. When nerves regenerate and pain returns, the procedure can typically be repeated.

Is the procedure painful?

The procedure is done under local anesthesia, so you should not feel sharp pain. You may feel pressure, warmth, or mild discomfort during the ablation. Some patients receive mild sedation for comfort. Soreness at the treatment sites for 1-2 weeks afterward is normal.

How many diagnostic blocks do I need before RFA?

Most insurance plans, including Medicare, require at least one successful diagnostic block showing 50% or greater pain relief. Some insurers require two positive blocks on separate occasions.

Can RFA be repeated?

Yes. When pain returns because the nerves have regenerated, RFA can be repeated. Most studies show that repeat procedures are similarly effective to the initial treatment.

Will RFA affect my ability to walk?

No. The genicular nerves targeted during RFA carry only pain signals. They do not control muscle movement. Your ability to walk, bend your knee, and perform daily activities should not be affected — and may actually improve as pain decreases.

What if the diagnostic block does not help?

If the diagnostic block does not reduce your pain by at least 50%, you are unlikely to benefit from RFA. Your provider will discuss alternative treatments, which may include other injection therapies, physical therapy modifications, or surgical consultation.

Key Takeaways

1. Genicular nerve blocks and RFA can provide 6-12 months of pain relief for chronic knee osteoarthritis
2. Diagnostic blocks are required first to confirm you are a good candidate
3. The procedure is minimally invasive and performed as an outpatient with local anesthesia
4. Medicare and most private insurers cover these procedures when conservative treatments have failed, though coverage varies by region
5. RFA can be repeated when pain returns after nerve regeneration
6. Talk to your doctor about whether nerve block procedures are appropriate for your specific situation

This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider to determine whether nerve block procedures are appropriate for your condition. Insurance coverage varies — verify with your specific plan before scheduling a procedure.