Genicular Nerve Block for Pain Management in Patients With Knee Osteoarthritis: A Randomized Placebo-Controlled Trial

Objective This study was undertaken to determine the efficacy of ultrasound-guided genicular nerve block (GNB) for the management of knee pain in patients with knee osteoarthritis. Methods We performed a 12-week parallel-group, placebo-controlled randomized trial of GNB. Within 2 weeks of randomization, patients with knee osteoarthritis in the active arm received 3 injections of 5.7 mg celestone chronodose (1 ml) and 0.5% bupivacaine (3 ml) to the inferomedial, superomedial, and superolateral genicular nerves; patients with knee osteoarthritis in the placebo arm received injections of normal saline. At baseline and at weeks 2, 4, 8, and 12, patients recorded their pain and disability on a 100-mm visual analog scale (VAS) (the primary outcome measure), the Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC), and the Intermittent and Constant Osteoarthritis Pain scale. Statistical significance was set at a 2-sided Type I error of alpha = 0.0125 for comparisons at each of the 4 time points. We used a global perceived effect scale to measure patient satisfaction. Results The 59 patients (36 female, 23 male) who completed the trial had a mean +/- SD age of 68.2 +/- 8.6 years. Patients in the active group reported improvements in pain scores at 2, 4, 8, and 12 weeks with a diminution of the effect over time. VAS scores at baseline and at weeks 2, 4, 8, and 12 in the active group (n = 31) versus placebo group (n = 28) were 6.2 versus 5.3 (P = 0.294), 2.7 versus 4.7 (P < 0.001), 3.2 versus 5.1 (P < 0.001), 3.9 versus 4.9 (P < 0.001), and 4.6 versus 5.1 (P = 0.055), respectively. Total WOMAC scores at baseline and at weeks 2, 4, 6, 8, and 12 in the active group versus the placebo group were 54.5 versus 48.1 (P = 0.177), 32.9 versus 44.4 (P < 0.001), 33.7 versus 45.8 (P < 0.001), 39.2 versus 44.8 (P = 0.001), and 42.65 versus 45.1 (P = 0.012), respectively. Conclusion GNB offers short-term pain relief for knee osteoarthritis.