Treating Chronic Knee Pain: Radio-Frequency Ablation of the Genicular Nerves

Why Do We Feel Pain?

Pain is the human body’s natural response to a harmful stimulus from our external environment or within our own bodies. This response is due to our neural pathways transmitting signals along peripheral nerves from the affected area to our central nervous system. This transmission allows us to perceive the stimulus as pain. 

Knee pain is one of the most common complaints among all patient populations. This experience may be the result of injury, arthritis, or various conditions and forms of chronic pain. The nerves often associated with chronic knee pain are the genicular nerves. This nerve group innervates the knee joint and includes the femoral, common peroneal, saphenous, tibial, and obturator nerves. These nerves operate similarly to many others previously described: some stimulus from the environment (such as an injury) or within our own bodies (such as arthritis) activates the genicular nerves, leading to signal transmission to the central nervous system. This produces the sensation of pain in or around the knee. When these pathways are stimulated or overstimulated to the point of interfering with daily activities, patients should begin to seek out therapeutic options. Radio Frequency Ablation (RFA) is one such example of a useful therapy for genicular knee pain.

What is Radiofrequency Ablation (RFA) for Nerve Pain?

Radiofrequency Nerve Ablation utilizes high-frequency electrical current that travels through carefully placed electrodes and produces thermal energy and heat at the tips. The heat at the electrode tips targets specific sensory nerves that are responsible for chronic pain. The applied heat of around 90°C essentially burns the nerves deemed problematic and forms a lesion that disrupts their ability to transmit pain signals. In other words, the very loud and disruptive nerve is silenced, thereby promoting pain relief. 

In general, the risk of complications associated with RFA therapy is low when conducted by a trained specialist. In most cases of complications, patients may experience temporary pain or burning sensations at target sites. The more rare examples of complications may involve reduced motor neuron functionality in an area while the lesion heals itself over the following months. This occurs if a motor nerve develops a lesion as well; however, prevention methods that seek to reduce this potential are always followed before thermal initiation.

What Does the RFA Process Look Like?

At the beginning of a patient’s treatment journey, most individuals are recommended conservative treatment, including physical therapy. If this type of pain management proves ineffective at providing longer-term relief or if patients are hoping to avoid or postpone surgery, ablation therapy may be a beneficial option. Generally, pursuit of radio frequency ablation therapy is a 2-part process. 

The first step is for two nerve blocks to be performed in the target region. These must provide 50% reduction in target pain for approval to be granted for ablation. These are typically administered one-week apart from each other and involve local anesthetic being administered around the target nerves. In the case of genicular knee pain, the anesthetic is administered around the genicular nerve radiofrequency ablation  branches in the extra-articular space. The resulting impact on the patient’s pain levels provide insight into what should occur when the nerves are silenced on a longer-term basis via radio frequency ablation. In short, these anesthetic nerve blocks are the diagnostic trials that help a patient-doctor team determine whether RFA could be effective.

A patient-doctor team may then move forward with the minimally-invasive radio frequency ablation procedure. This typically begins with moderate sedation and the small areas around injection sites being numbed. Fluoroscopy (live X-Ray imaging) is then used to guide needles to the target locations. Electrodes are then inserted where the needles were placed. The radio frequency ablation software is then run by a trained specialist. This begins with an electrical current being sent to the electrodes to confirm that no motor neurons are impacted. The most common sign that electrode locations should be adjusted is if significant twitching of the target area or extremities is observed. Once the physician feels confident to continue, the thermal ablation is then activated and the nerves are burnt for 90 to 120 seconds at around 90ºC. The total process is not very long, typically lasting between 30 and 60 minutes.

How Can Genicular Radiofrequency Ablation Help You?

When radiofrequency ablation therapy was introduced in 1975, it was first utilized for the treatment of back pain. The scope of this treatment has since expanded and can now be use for the treatment of other sources of pain, including knee pain and arthritic pain. If the genicular nerves are found to be the source of one’s chronic pain, radiofrequency ablation of the genicular nerves may be an effective treatment option.

If you have chronic pain and hope to reduce it with the radiofrequency ablation procedure, our trained physicians at Ospina Medical may be able to help you. Book your appointment with Dr. Matthew Kohler or Dr. Raj Maniam today to get started on this journey and improve your quality of life!

Written By: Cherubina Ruban

Edited By: Camden Rowe