Genicular Nerve Radiofrequency Ablation for Painful Knee Arthritis: The Why and the How

Thermal GNRFA differs from all other treatment alternatives because this procedure causes denaturing of the 3 sensory nerves primarily responsible for transmitting knee pain from an arthritic joint to the central nervous system. In this procedure, heating occurs from an intense alternating electrical field at the tip of the cannula, which produces sufficient heat to denature the proteins in the target tissue. The accepted heating parameters for this procedure are 70° to 80°C for 60 or 90 seconds. A commonly raised question is whether this procedure precipitates a Charcot-type joint. The Charcot joint involves much more than reduced innervation; it occurs in the context of chronically compromised vascularity and altered soft-tissue characteristics as well as peripheral neuropathy. Moreover, a Charcot-type joint does not develop because the deafferentation of the weight-bearing joint is partial3. To our knowledge, no Charcot-type joints have been reported after this procedure. Conversely, data from an animal study have shown that selective joint denervation may lead to the progression of knee OA4. The ablation procedure is done outside the knee joint, unlike alternatives such as intra-articular therapies and surgery. The effectiveness of nonsurgical knee OA interventions in alleviating pain and improving joint function is generally inadequate1. However, GNRFA appears to be an emerging alternative for patients who have had failure of conservative and surgical treatments. It is not uncommon in our clinical practice for patients to achieve adequate pain control following ablation for up to 1 year. GNRFA provides temporary relief from symptomatic knee OA because it does not eliminate the potential for peripheral nerve regrowth and regeneration, and thus pain, to return.