Genicular Nerve Radiofrequency Ablation for Select Patients with Persistent Pain

An option for difficult-to-treat chronic knee pain

By Michael Schaefer, MD, and Robert Bolash, MD

Chronic knee pain is often a challenging condition to treat. Pharmacologic interventions commonly fail to provide adequate relief and can be limited by adverse effects. Corticosteroid injections provide only temporary relief, while hyaluronate injections are expensive and controversial. Newer “regenerative” injection treatments such as stem cells and platelet-rich plasma are still considered experimental and are often not covered by insurance. Surgical interventions for joint preservation are limited, and total joint replacement is often not an option for young or obese patients. Even after arthroplasty, unremitting knee pain continues to afflict some patients.

Radiofrequency ablation for genicular nerves (GNRFA) is a relatively new and lesser-known treatment option that is proving effective for certain patients. A randomized controlled trial demonstrated significant improvement with GNRFA throughout the 12-week follow-up period. At Cleveland Clinic, we consider patients for GNRFA who have failed or are excluded from other treatment modalities. The process begins with a diagnostic genicular nerve block.

Diagnostic Process

Genicular nerve blocks can be performed under fluoroscopic or ultrasound guidance. Nerves are targeted adjacent to the periosteum on the medial aspect of the tibia, and at both the medial and lateral aspects of the femur at the junctions of the shaft and the epicondyle.

Under fluoroscopic guidance, we approach the target by introducing a spinal needle from either an anteroposterior or lateral entry point with the final position residing adjacent to the bone. After negative aspiration, some physicians elect to administer contrast to exclude vascular uptake, avoiding a false negative result. To conclude the procedure, 2 mL of local anesthetic is deposited on each of the superolateral, superomedial and inferomedial genicular nerves.

While GNRFA performed under fluoroscopic-guided requires a procedure room, the ultrasound-guided procedure can be performed conveniently in the outpatient clinic setting without radiation exposure. In addition, two recent studies suggest ultrasound guidance improves accuracy of the diagnostic block by localizing arteries and soft tissues adjacent to the nerves. Again, all three genicular nerves are routinely injected – the superomedial, superolateral and inferomedial branches. Other branches have been reported to innervate the knee, but they are not suspected to carry as much nociceptive output from the joint, so injecting them may be less effective. In patients who report pain only on the medial side of the knee, the physician may choose to inject only the medial-sided nerves.

When to Proceed to Therapeutic Ablation

If the diagnostic injection produces at least 50 percent pain relief on a numeric rating score reduction, the patient is deemed a candidate for GNRFA. Exclusions include systemic or local infection and electrical devices implanted in the region of the radiofrequency ablation. Additional vigilance is required in the presence of anatomic deformities or implantable cardiac rhythm devices when considering GNRFA because of the potential for a defibrillator to interpret radiofrequency as a shockable dysrhythmia. GNRFA can successfully be performed with arthroplasty or with other orthopaedic hardware in place.

The GNRFA procedure is typically performed with local anesthetic, although moderate IV sedation may be offered. Either ultrasound or fluoroscopic guidance may be used. Following local anesthetic infiltration, a radiofrequency cannula is guided in proximity to the locations of each nerve. Sensory stimulation can be used to confirm accurate placement. Motor stimulation is also performed to ensure the absence of adjacent motor fibers.

After positive confirmation of sensory placement and negative motor testing, 2 mL of 2 percent lidocaine is administered adjacent to the nerve to mitigate pain associated with radiofrequency lesioning. Radiofrequency ablation is performed at a temperature of 70 C for 90 seconds.

Postprocedurally, patients remain ambulatory and often return to work on the subsequent day. A few days of localized soreness is expected following the procedure with typical final results realized within one week.

Pain Relief Can Be Long-lasting

While Choi showed that relief continued for 12 weeks, in our practice, we have seen many patients sustain even lengthier analgesia, at times approaching a year. The GNRFA may be repeated if symptoms return.

GNRFA is a suitable management option for a subset of patients with inadequate response to more conservative modalities and even for those with postsurgical refractory knee pain.

Dr. Schaefer is Director of Musculoskeletal Rehabilitation at Cleveland Clinic.

Dr. Bolash is an anesthesiologist and interventional pain management specialist in the departments of Pain Management and Evidence Based Pain Research.

Jun. 2, 2016 / Orthopaedics / Research

This article appeared in ConsultQD of the Cleveland Clinic

Genicular Nerve Radiofrequency Ablation for Select Patients with Persistent Pain


Aquatic Physical Therapy

Aquatic Physical Therapy uses the unique properties of water for strengthening, stretching, balance and endurance training. Land based physical therapy uses modalities to relieve pain, stretching muscles and equipment for strengthening.  There are times exercise is best performed in water to place less stress on joints.  This is the essence of Aquatic Physical Therapy.

In addition to reducing stress across arthritic joints, it also increases resistance when moving through the water and the ability to work several body parts at one time.  Below is a list taken from a section on the American Physical Therapy Association’s website on Aquatic Physical Therapy listing some of these benefits.

Aerobic capacity/endurance conditioning
Balance, coordination and agility
Body mechanics and postural stabilization
Gait and locomotion
Muscle strength, power, and endurance

Interventions used in Aquatic Physical Therapy include, but are not limited to, therapeutic exercise, functional training, manual therapy, breathing strategies, electrotherapeutic modalities, physical agents and mechanical modalities using the properties of water and techniques unique to the aquatic environment.

So the next time your physician recommends physical therapy ask if Aquatic Physical Therapy is right for you.

Click here to learn more about Aquatic Physical Therapy


If I run, will it cause knee arthritis? Probably not.

Exercises like running can provide numerous health benefits. It has been thought in the past that running may cause or increase the risk for the wear and tear arthritis known as osteoarthritis. Recent data suggest that in non-elite runners, i.e. recreational runners, there does not appear to be an increased risk, but rather a possible protective effect.  This comes with some important and practical points. Running needs to be habitual and the less the body weight, i.e. BMI, the less the chance of developing knee arthritis. Below is an abstract discussing this from the 2014 American College of Rheumatology Annual Meeting;

Habitual Running Any Time in Life Is Not Detrimental and May be Protective of Symptomatic Knee Osteoarthritis: Data from the Osteoarthritis Initiative.

Here are some tips that may keep you running happier and healthier:

  • Use the right fuel. Eat well; Eat healthy.  You can’t run away from a bad diet.
  • Take care of yourself including health issues. Ask your doctor if you’re not sure.
  • Optimize you mechanics. From your shoes to your form. Be efficient.
  • Stay strong. Weight training and core strengthening protect the joints.
  • Remember to rest. This includes sleep and breaks between runs.
  • Know your limits. Listen to your body. It doesn’t lie.
  • Have a plan and make running a “habit”.
  • Most of all have fun! 


Botulinum Toxin for Treatment of Knee Arthritis Pain: Not just for wrinkles anymore

Knee pain due to degenerative arthritis is a common and disabling problem.  In the United States alone, approximately 700,000 total knee replacements are performed annually.  Nonsurgical treatments include physical therapy, steroid injections, viscosupplementation injections, i.e. hyaluronic acid and regenerative injection therapy such as PRP.  Acupuncture has been used.

Recent research is showing that botulinum toxin may be helpful in decreasing knee pain due to osteoarthritis.  Botulinum toxin has been used in clinical medicine to treat muscle spasticity, excessive sweating and headaches.  Botulinum toxin has also gained attention for its cosmetic use in decreasing wrinkles.

Botulinum toxin works by inhibiting the release of acetylcholine, a chemical released from the ends of nerve cells.  This blocks muscle function and may last up to 3 months.  The mechanism for pain relief is uncertain, but recent studies show that botulinum toxin blocks the release of substance P, calcitonin gene-related peptide, and glutamate, which are chemicals in joints that cause pain. This decrease in pain-mediating neurotransmitters directly blocks peripheral sensitization and indirectly blocks central sensitization (Ref: Krug HE, P L, P M. Intra-articular botulinum toxin A is effective for chronic inflammatory arthritis pain but not acute inflammatory arthritis pain as measured by spontaneous and evoked pain behaviors. Arthritis Rheum 2007;56:S519.)  In addition, botulinum toxin inhibits Rho GTPase by the ADP-ribosylation of amino acid ASn-41, and Rho GTPase is necessary for activating interleukin-1. Because of the inhibition of interleukin-1 activation, cartilage degradation may be decreased in persons with osteoarthritis. This is good news. (Ref: Aoki KR. Evidence for antinociceptive activity of botulinum toxin type A in pain management. Headache 2003;43:9-15.). Read more in the recent article in December 2016 PM&R here.

Though not currently approved by the FDA for treatment of knee osteoarthritis, recent research demonstrates that botulinum toxin may be effective for the treatmnet of knee arthritis.  In my opinion, future applications may include combining botulinum toxin with PRP or prolotherapy for the treatment of knee arthritis and other painful conditions involving muscles, tendons, ligaments and joints.   See link to Arthritis Foundation blog post about botulinum toxin and knee pain below.

Studies Suggest Botox May Ease Osteoarthritis Pain – read more from the Arthritis Foundation.

Platelet Rich Plasma with Hyaluronic Acid Injection for Knee Osteoarthritis: Better When Combined?

Hyaluronic acid is a “viscosupplment” approved by the FDA of treatment of knee osteoarthritis. It is a substance that is naturally present in our joints and when injected acts to cushion the joint and provide pain relief. It however has not been shown to reverse or slow down osteoarthritis. The standard treatment for knee osteoarthritis requires either a single or series of knee injection every 6 months to be effective. Mayo Clinic – Hyaluronic Acid (Injection Route).

Platelet Platelet Rich Plasma is 5-10x concentration of one’s own blood  platelets and associated platelet derived growth factors. These growth factors have been shown to heal and repair damaged tissue including cartilage.

A recent scientific article examined the combination of hyaluronic acid and PRP in the treatment of severe knee osteoarthritis. This is a very small study, but the results are very encouraging. Future research is pending, but based on what we know of these two naturally occuring substances we should be optomistic.

Clinical effectiveness in severe knee osteoarthritis after intra-articular platelet-rich plasma therapy in association with hyaluronic acid injection: three case reports. Chen SH1, Kuan TS2, Kao MJ3, Wu WT1, Chou LW4.Clin Interv Aging. 2016 Sep 8;11:1213-1219.
Prolotherapy which corrects ligamentous instability, i.e. loose joint in combination with PRP/Hyaluronic Acid in theory may have better outcomes. I am encouraged that the research continues to explore natural regenerative treatments and demonstrates significant positive results.



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