Cooled Genicular Radiofrequency Ablation Versus Conventional Genicular Radiofrequency Ablation for the Treatment of Chronic Knee Pain: A Prospective Study

This prospective observational study seeks to compare pain relief at 1 month, 3 months and 6 months following cooled radiofrequency ablation vs conventional genicular nerve ablation in patients with chronic knee pain.

Both cooled RF and conventional genicular nerve ablation use the electrical current produced by radio waves to destroy a part of nerve tissue, creating a lesion and relieving pain (Kapural and Mekhail 2001). The conventional probe emanates heat that can damage surrounding tissues, and the lesion produced is limited in size. Cooled radiofrequency (RF) probes have a system of water running through the probe tip that keeps the probe tip at a lower temperature (Lorentzen 2015). Coolief produces larger spherical-shaped lesions, meaning an increased area of nerve destruction with less heat damage to surrounding tissues (Menzies and Hawkins 2015).

In 2017, the FDA cleared the Cooled radiofrequency thermal treatment device (Coolief, Halyard Health, Alpharetta, GA, USA) for knee osteoarthritis. McCormick et al investigated 33 patients with knee osteoarthritis pain, and after 6 months, 35% of patients had at least 50% or greater reduction in Numeric Rating Scale (NRS) for Pain, and 19% had complete pain relief. In another study by Davis et al, they compared, prospective, multicenter, randomized trial of 151 patients that compared cooled radiofrequency ablation genicular against intraarticular steroid injection. At 6 months, the cooled radiofrequency ablation group had more favorable outcomes in NRS: pain reduction 50% or greater was 74.1% in the ablation group versus 16.2% in the intraarticular group. Henry Ford Hospital Pain center introduced cooled radiofrequency ablation treatment modality in 2017 and it's currently being used in patients with chronic knee osteoarthritis and post-surgical knee pain.

This study will follow patients who have been diagnosed with chronic knee osteoarthritis or post-surgical knee pain and are scheduled to undergo Coolief or conventional ablation to treat their chronic knee pain. At 1, 3 and 6 months following their treatment, the study team will call patients on the phone to give them to ask about their pain and disability, using the NRS for pain, WOMAC for knee pain, and ODI questionnaire. Baseline and post-treatment scores will be compared to determine if Coolief elicits a more pronounced impact on reduced pain and disability than the conventional technique.

We expect to find a greater reduction in pain and disability experienced by patients who undergo the newer, cooled radiofrequency ablation when compared to the conventional ablation technique, at 1, 3- and 6-months after the procedure. The information gained from this study will be used to guide future ablation treatment, to ensure that patients receive the most effective pain relief treatment for their chronic knee pain.