Diagnostic Genicular Nerve Block May Predict Treatment Outcomes of Cooled RFA in Chronic Knee Pain
A diagnostic genicular nerve block may not represent an accurate predictor of outcomes of cooled radiofrequency ablation.
Genicular nerve cooled radiofrequency ablation may effectively relieve chronic knee pain associated with osteoarthritis and improve function for up to 6 months, according to research presented at the American Academy of Pain Medicine 2018 Annual Meeting, held April 25 to 29, 2018, in Vancouver, British Columbia, Canada. In addition, a diagnostic genicular nerve block may not represent an accurate predictor of outcomes from this procedure.
The investigators sought to evaluate the predictive value of a diagnostic genicular block for outcomes of a subsequent cooled radiofrequency ablation of the genicular nerve for osteoarthritis-associated knee pain. For this study, patients with chronic knee pain were randomly assigned to receive a diagnostic genicular nerve block or no block (25 patients, 35 knees) before cooled radiofrequency ablation.
The ablation procedure was carried out only in patients who experienced ≥50% pain reduction from the diagnostic nerve block (29 patients, 36 knees). The study's primary outcome was ≥50% pain relief at the 6-month follow-up.
Pain relief ≥50% at 5 months after the ablation procedure was observed for 15 (41.7%) of 36 knees of study participants who received the diagnostic genicular nerve block, and for 15 (42.9%) of 35 knees in patients who had not received the block (P =.92).
A 15-point reduction in the 24-item Western Ontario and McMaster Universities Osteoarthritis index was observed for 44.8% of all study participants, and a global perception of "improved" or "very much improved" change was reported by 38.6% of patients at 6-month follow-up.
"This study demonstrated clinically meaningful improvements in pain and physical function up to 6 months following [cooled radiofrequency ablation]," concluded the study authors. "A diagnostic genicular nerve block with a threshold of ≥ 50% pain relief did not improve the rate of treatment success," they added.
McCormick Z, Reddy R, Korn M. Do diagnostic genicular nerve blocks predict treatment outcomes of cooled radiofrequency ablation in patients with chronic knee pain from osteoarthritis? A prospective randomized trial. Presented at: American Academy of Pain Medicine 2018 Annual Meeting; April 25-29, 2018; Vancouver, British Columbia, Canada. Abstract 144.