Long-Term Pain and Functional Outcomes After Cooled Genicular Radiofrequency Ablation With or Without Adjunctive Intra-Articular Botulinum Toxin Type A in Knee Osteoarthritis.

Abstract

BACKGROUND Cooled genicular radiofrequency ablation (CRFA) is used to treat symptomatic knee osteoarthritis (OA), although treatment response may decline over time. This study evaluated 24-month outcomes of CRFA alone versus CRFA combined with intra-articular botulinum toxin type A (BoNT-A). MATERIAL AND METHODS In this retrospective observational comparative-effectiveness cohort study, 90 patients with moderate-to-severe knee OA underwent CRFA alone (n = 50) or CRFA plus intra-articular BoNT-A (n=40). The combination group received BoNT-A at baseline and a planned repeat injection at ~12 months. Pain and function were assessed using the Numerical Rating Scale (NRS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The primary durability endpoint was the between-group difference in longitudinal NRS trajectories over 24 months, assessed using adjusted mixed-effects modeling. RESULTS Both groups demonstrated substantial early improvement; outcome trajectories diverged after ~12 months. Significant treatment-by-time interactions were observed for NRS (ß=-0.84, 95% confidence interval [CI] -1.21 to -0.47; P=0.0002) and WOMAC outcomes (ß=-6.3, 95% CI -9.4 to -3.2; P=0.0003). At 24 months, mean observed NRS scores were 4.2±2.3 after CRFA alone and 1.8±0.9 after CRFA plus BoNT-A; responder rates were 51.1% and 86.5%, respectively (P=0.0004). CONCLUSIONS In this retrospective observational cohort, a longitudinal treatment pathway combining CRFA with intra-articular BoNT-A was associated with more sustained pain relief and functional improvement over 24 months than CRFA alone. Prospective randomized studies are needed to confirm these findings and clarify the independent contributions of adjunctive and repeat intra-articular BoNT-A.