Radiofrequency (heat treatment) is used to kill the small branches of the sensory nerves to the knee (genicular nerves). The procedure is called a radiofrequency neurotomy.
Nerve blocks are used to confirm that nerve irritation is the problem and source of pain. But a nerve block only provides temporary effects. Once the pain comes back, then radiofrequency ablation is a good choice to end painful symptoms permanently.
The neurotomy is minimally invasive. The surgeon creates a tiny tunnel through the skin and soft tissues down to the bone. Fluoroscopy (real-time X-rays) and sensory stimulation are used to make sure the surgeon is close enough to the nerve to make accurate contact.
After the nerve is located then a radiofrequency probe is passed through the tunnel to the nerve. The tip of the electrode is heated up to 70 degrees Celsius (about 160 degree Fahrenheit) for 90 seconds. This ensures that the nerve is destroyed and no further pain transmission can get through.
Complications and problems along the way can occur but these are uncommon. Sometimes patients report “unbearable” pain during the procedure. This response is likely from sensitive nerve endings on the bone where the radiofrequency probe touches.
You should consider the treatment a success if the patient got at least 50 per cent improvement in pain for more than a 24-hour period. Anything less than those criteria are considered a failed treatment.
There are times when the RF treatment is not successful. This is most likely because the target nerves vary in their anatomic location. And sometimes there are extra branches that still supply the joint with nerve impulses.
Pain is relieved only if and when all branches of the sensory nerves to the knee are found and destroyed. If the first procedure doesn’t completely eliminate the pain, neurotomy can be repeated a second and even third time.