Conventional Thermal versus Water-Cooled Genicular Nerve Radiofrequency Lesioning: A Retrospective Chart Review

Background: Genicular nerve radiofrequency lesioning (RFL) is an interventional approach to chronic knee pain. It is currently unknown whether conventional thermal RFL (CT-RFL) or watercooled RFL (WC-RFL) yields better outcomes. Objective: The objective of this research was to analyze and compare outcomes of genicular nerve conventional thermal radiofrequency lesioning (CT-RFL) vs water-cooled radiofrequency lesioning (WC-RFL) for the treatment of chronic knee pain. Study Design: We used retrospective chart review. Setting: The research took place in an outpatient pain clinic at a large academic medical center. Methods: Patients who participated in the study were those aged 18 and older who received genicular nerve RFL for chronic knee pain between January 1, 2014 and December 31, 2016. Random intercepts models were used to examine Visual Analog Scale (VAS) pain scores across the first year of follow-up, adjusting for age, gender, and prior history of knee surgery. Results: Overall, VAS scores were significantly reduced from baseline (mean = 6.66, standard deviation [SD] = 1.36) by 1.46 points during the first follow-up month (95% confidence interval [CI], 0.6-2.3, P = .001), 2.22 points during the second follow-up month (95% CI, 1.4-3.1, P = < .001), and 1.24 points during the sixth follow-up month (95% CI, 0.1-2.4, P = .035) but were not significantly reduced at other months during the one-year followup time period. There was no statistically significant difference in follow-up pain scores (mean difference = 0.73, 95% CI, -0.14-1.59, P = .116) or rates of complications (P = .10, 2-tailed Fisher exact test) between RFL types. Limitations: Study shortcomings include patient loss to follow-up, heterogeneity of CT-RFL techniques, and heterogeneity of study patients. Conclusions: Genicular RFL is a promising strategy for long-term management of treatment-resistant chronic knee pain. In this study, no significant difference in outcomes was detected between CT-RFL and WC-RFL techniques. Larger prospective studies are warranted to compare outcomes of these techniques and guide future care. Key words: Radiofrequency lesioning, knee pain, chronic pain, osteoarthritis, genicular, cooled radiofrequency lesioning, water-cooled radiofrequency lesioning, conventional radiofrequency lesioning