Knee pain affects as many as 20% of adults over the age of 50 years. The most common cause of knee pain among older adults is arthritis. Chronic osteoarthritis (OA) of the knee is a condition that causes serious pain. Knee pain is not often effectively managed with pharmacological treatments, joint injections, and physical therapy. An effective alternative for chronic knee pain is radio frequency ablation, which is also called a neurotomy.
In the U.S., around 600,000 surgical knee replacements are performed each year. According to statistics, 10% of women and 7% of men are at risk to receive a knee replacement at some point during their lives. However, around 20% of patients continue to have long-term pain after the total knee replacement.
What are Genicular Nerves?
The knee joint is supplied with various nerves, including the peroneal, femoral, tibial, saphenous, and obturator nerves. The branches from these knee joint are called the genicular nerves, which consist of the superior lateral, middle, superior medial, inferior lateral, inferior medial, and recurrent tibial genicular. These nerves are the main innervation for the knee joint.
Who needs a Genicular Nerve Block?
People who are candidates for radiofrequency ablation of the genicular nerves include anyone who:
- Has chronic knee pain due to OA
- Has a failed knee replacement
- Is not able to have a knee replacement
- Wants to avoid knee surgery
Is Radiofrequency Ablation Effective for Knee Pain?
In a study involving patients with chronic OA knee joint pain, researchers evaluated radiofrequency ablation applied to the articular nerve branches, which are the genicular nerves. In the study, 38 patients had severe knee pain that had persisted for more than 3 months, and these participants had a previous positive response to a diagnostic genicular nerve block.
After the radiofrequency ablation procedure, patients were evaluated using the visual analogue scale and Oxford knee scores. According to results, all radiofrequency patients has less knee joint pain at 4 weeks compared to participants who did not receive treatment. In addition, around 65% reported more than 50% reduction in knee pain at the 12-week follow-up evaluation.
How Do I Prepare for the Procedure?
Before the procedure, the doctor will ask you questions about your condition, take a medical history, and perform a physical examination. You should notify the doctor if you are allergic to latex, medical solutions, or medications. If you take blood-thinning agents, the doctor will have you hold these for several days before the procedure. When you arrive at the surgical center, a nurse will go over the procedure risks and benefits and have you sign a consent form. Be sure to arrange to have someone drive you home.
What can I Expect During the Procedure?
Radiofrequency neurotomy is performed with the patient awake but under light sedation. The nurse will place an IV catheter in your arm so the anesthesiologist can administer medication. The knee region will be cleaned and numbed using a local anesthetic. Using real-time x-ray, the doctor will insert a needle with an electrode into the treatment area. After assuring placement is correct, high-frequency electrical energy is passed through the electrode to heat up and ablate the sensory nerve. After this, the needle and electrode are removed and a bandage is applied.
What Happens After the Procedure?
A nurse monitors you in the recovery room for 20-30 minutes. Usually, patients go home within 1-3 hours. You can expect some initial knee discomfort and should rest for 1-2 days. Most patients can return to normal activities in a few days. You will notice marked decrease in pain and continued improvement after 3-5 days. Long-lasting pain relief is expected, but some nerves do repair themselves so pain may return.
Choi WJ, Hwang SJ, Song JG, et al. (2011). Radiofrequency treatment relieves chronic knee osteoarthritis pain: a double-blind randomized controlled trial. Pain, 15293), 481-487.