A Prospective Randomized Comparison of the Efficacy of Ultrasound- vs Fluoroscopy-Guided Genicular Nerve Block for Chronic Knee Osteoarthritis.

BACKGROUND: Recently, genicular nerve block and radiofrequency ablation were introduced to alleviate knee pain in patients with chronic knee osteoarthritis. Both ultrasound- and fluoroscopy-guided genicular nerve blocks have been used. However, whether one is superior to the other remains unknown.OBJECTIVES: The present study compares the efficacy of ultrasound- vs fluoroscopy-guided genicular nerve blocks.STUDY DESIGN: This research used a prospective randomized comparison design.SETTING: The study took place at a single pain clinic within a tertiary medical center in Seoul, Republic of Korea.METHODS: From July 2015 to September 2017, a randomized controlled study was performed to analyze the difference in the efficacy of ultrasound- vs fluoroscopy-guided genicular nerve blocks. The Numeric Rating Scale (NRS-11), Western Ontario and McMaster Universities Arthritis Index (WOMAC), Global Perceived Effect Scales (GPES), and complications were evaluated pre-procedure, and 1 and 3 months after genicular nerve block.RESULTS: A total of 80 patients were enrolled and randomly distributed to groups U (ultrasound-guided, n = 40) and F (fluoroscopy-guided, n = 40). Those who were lost to follow-up or had undergone other interventions were excluded, resulting in 31 and 30 patients in groups U and F, respectively. No differences in NRS-11 or WOMAC were observed between the 2 groups at baseline or during the follow-up period. GPES and complication rates were also similar between both groups.Limitations: We were unable to perform double-blind randomization and did not evaluate patients' baseline emotional states.CONCLUSIONS: Pain relief, functional improvement, and safety were similar between groups receiving ultrasound- and fluoroscopy-guided genicular nerve blocks. Therefore, either of the 2 imaging devices may be utilized during a genicular nerve block for chronic knee pain relief. However, considering radiation exposure, ultrasound guidance may be superior to fluoroscopic guidance.The study protocol was approved by our institutional review board (2015-0369), and written informed consent was obtained from all patients. The trial was registered with the Clinical Research Information Service (KCT 0002846). This work was presented in part as D-H Kim's MS thesis at the University of Ulsan College of Medicine (2018).Key Words: Genicular nerve block, ultrasound, fluoroscopy, knee osteoarthritis, Numeric Rating Scale, The Western Ontario and McMaster Universities Osteoarthritis Index.