Intra-Articular Polyacrylamide Hydrogel Injections Improve Pain and Function in Knee Osteoarthritis: A Multicenter Retrospective Study

Objective To evaluate the real-world effectiveness of intra-articular (IA) 2.5% polyacrylamide hydrogel (iPAAG) injections in reducing pain and improving function in patients with knee osteoarthritis (KOA). Design: This multicenter retrospective study analyzed outcomes from 387 patients (593 knees) treated with IA 2.5% iPAAG hydrogel. Patient-reported outcomes were assessed over 12 months. Pain was measured using the Visual Analogue Scale (VAS), and function was evaluated with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Results At 12 months post-injection, mean VAS scores decreased by 2.5 points, mean total WOMAC scores decreased by 13.4 points, and the WOMAC function subscale decreased by 7.0 points. Improvements were consistent across age, sex, and BMI categories. Patients with Kellgren-Lawrence Grade 2 KOA demonstrated greater benefit compared to those with Grades 3 and 4. No unexpected safety concerns were reported. Conclusions IA 2.5% iPAAG injections significantly reduced pain and improved function in KOA patients in a real-world setting. These findings support its role as a non-surgical treatment option for symptomatic KOA, particularly in earlier disease stages.