Intra-Articular Steroid Injection with or Without Pulsed Radiofrequency in Knee Osteoarthritis: A Retrospective Comparative Study

Abstract

Background and Objectives: Knee osteoarthritis is a major cause of chronic pain and disability. Because the benefit of intra-articular corticosteroid injection is often limited, this study compared fluoroscopy-guided corticosteroid injection alone with corticosteroid injection combined with pulsed radiofrequency (PRF). Materials and Methods: This retrospective comparative study included 386 consecutive patients with symptomatic knee osteoarthritis treated with fluoroscopy-guided intra-articular corticosteroid injection alone (IAS, n = 190) or combined with PRF (IAS + PRF, n = 196). Pain and function were assessed using the Visual Analog Scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at baseline and 1 week, 1, 3, and 6 months. The primary endpoint was the 6-month VAS score. Baseline-adjusted linear mixed-effects models were the primary analyses, with propensity score-matched analyses as sensitivity analyses. Results: Both groups showed significant improvements in pain over time. In the primary baseline-adjusted analyses, adding PRF was associated with greater early- and mid-term pain reduction, including significantly lower VAS scores at the 6-month primary endpoint and higher rates of clinically meaningful pain improvement (≥50% response). However, this adjusted difference was modest (below the minimal clinically important difference) and was no longer statistically significant after propensity score matching (6-month VAS median 5.0 in both groups; p = 0.763), indicating that baseline imbalance contributed to the apparent advantage. Conclusions: In baseline-adjusted analyses, adding PRF to intra-articular corticosteroid injection was associated with more favourable early- and mid-term pain outcomes than corticosteroid injection alone, although the difference was modest and was not confirmed after propensity score matching. Given the retrospective, non-randomized design and baseline imbalance, these findings should be considered hypothesis-generating. Prospective randomized, sham-controlled studies with longer follow-up are needed to clarify the role of PRF as an adjunctive treatment for knee osteoarthritis.