Evaluation of Genicular Nerve Blocks Durations With and Without Corticosteroid: A Single-blind, Randomized Controlled Trial.

Background: Genicular nerve blocks (GNBs) are commonly performed prior to performing  radiofrequency ablation (RFA) to assess RFA's potential efficacy. Typically, GNBs are commonly performed with local anesthetic only. The duration of efficacy of GNBs has not been investigated much in the literature.

Objectives: The primary goals of this study were to evaluate for any differences in response to GNBs between using local anesthetic only versus local anesthetic and corticosteroid, and assess for the potential therapeutic benefit of GNBs by examining pain relief percentage, pain relief duration, and change in pain scores.

Study design: Randomized prospective trial.

Setting: Fluoroscopy suite at an urban academic teaching hospital.

Methods: Fifty patients with chronic knee osteoarthritis were randomly assigned to undergo a GNB done under fluoroscopic guidance with either bupivacaine only (n = 24, the control group) or bupivacaine and triamcinolone (n = 26, the experimental group). Baseline and postprocedure pain scores were collected on the day of the procedure. Patients were then called at postprocedure 24 hours, 2 weeks, and 6 weeks and asked their maximum percentage of pain relief, duration of pain relief, and Numeric Rating Scale (NRS-11) scores, which were compared between the 2 groups. Associations between these factors and Kellgren-Lawrence Classification of Osteoarthritis scores, body mass index, age, gender, race, and baseline pain scores were also assessed.

Results: The mean duration of pain relief was significantly higher in the group administered a corticosteroid (0.87; SD, 0.29 days) compared to the group not administered a corticosteroid (0.64; SD, 0.43 days) at 24 hours postprocedure. No significant differences were found between the 2 groups in pain relief percent, pain relief duration, or NRS-11 scores at any of the 3 time points. No significant difference in changes from baseline NRS-11 scores over time were found between the 2 groups. No significant associations were found between pain relief percent, pain relief duration, and NRS-11 scores regarding age, gender, body mass index, race, Kellgren-Lawrence scores, and baseline pain scores at postprocedure days one, 14, and 42.

Limitations: This was a single-blind, single-center study. It lacked a follow-up at 6 weeks postprocedure, lacked a placebo group, and had a small sample size.

Conclusion: The addition of a corticosteroid to local anesthetic for GNB may prolong initial analgesic effects within the first postprocedure 24 hours. However, there is no analgesic difference in the weeks following a GNB between procedures done with local anesthetic only or local anesthetic and corticosteroid. These findings suggest that there is a lack of therapeutic benefit and effect on relief duration with using  corticosteroids in GNBs.