Cooled radiofrequency ablation versus cryoneurolysis for the symptomatic management of pain in knee osteoarthritis: A prospective, randomized, sham-controlled, double-blind trial.

Abstract Background Knee osteoarthritis is a disease linked to severe pain and disability and several methods have been used to aid alleviate its symptoms, with varying degrees of success. Cooled radiofrequency ablation (CRFA) and cryoneurolysis (CRYON) are two novel methods under investigation for their capacity to control pain in knee osteoarthritis, while keeping a low complication rate. In this study the two methods will be compared with sham surgery, giving us an opportunity to compare their results. Methods In this prospective, randomized, sham-controlled, double-blind trial 60 patients suffering from knee osteoarthritis will be recruited using a diagnostic block of the genicular nerves under ultrasound guidance. Three groups will be created: cooled radiofrequency ablation group (24 patients), cryoneurolysis group (24 patients) and sham group (12 patients), through software randomization. Target of the interventions will be the three main genicular nerves; superior medial, superior lateral and inferior medial as well as the suprapatellar branch. The primary objective of this clinical trial is to evaluate the efficacy of CRFA or CRYON in comparison to sham surgery at 2-, 4-, 12- and 24-weeks post intervention using the Numerical Rating Pain Scale. Secondary objectives will be the safety of the 2 main techniques, as well as the clinical outcomes at 12- and 24-weeks post intervention using the Knee Injury and Osteoarthritis Outcome Score, the Oxford Knee Score and the 7-point scale of Patient Global Impression of Change. Discussion These two novel techniques are able to block the pain transmission through the genicular nerves via different ways. In contrast to cryoneurolysis treatment, where the literature is scarce, the method of CRFA has been well documented in the past. This will be the first clinical trial to compare them to sham surgery and draw conclusions about their safety and efficacy. The main genicular nerves as targets for cryoneurolysis will also be utilized for the first time. The institutional review board (IRB) of our University Hospital has approved the study (11846/05/10/2021) and written informed consent from participating patients would be obtained. Trial registration ISRCTN87455770 https://doi.org/10.1186/ISRCTN87455770