Usefulness of Polyacrylamide hydrogel for osteoarthritis of the knee

Administration of Polyacrylamide hydrogel intra-articular injection proved to be safe and effective for knee osteoarthritis in the long term.

To study the long safety and efficacy of Polyacrylamide hydrogel (PAAG) injection with previously demonstrated efficacy and safety up to week 26 in knee osteoarthritis (OA).

Conducted across multiple centres, this open-label study enrolled individuals with symptomatic and radiographic knee osteoarthritis (OA). The primary endpoint measured was the level of pain assessed using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain scale at 13 weeks. Patients were followed up to 26 weeks before continuing to an extra 26-week extension phase.

Secondary efficacy measures included stiffness and function subscales by the WOMAC, Patient Global Assessment (PGA) and the percentage of OARSI/OMERACT responders. Monitoring the adverse events (AEs) was a part of safety assessments.

Forty-nine participants (mean age of 70 years) underwent an ultrasound-guided iPAAG 6 ml intra-articular injection. Out of these, 46 completed the extension phase up to 52 weeks. Over this phase, there was a noteworthy reduction in the WOMAC pain score from the starting point to 52 weeks (a reduction of 17.7 points (95% CI − 23.1; − 12.4); p < 0.0001). Sustained improvements were also detected for WOMAC stiffness (a decrease of 11.0 points), physical function (a decrease of 18.0 points), and Patient Global Assessment (PGA) (a decrease of 16.3 points).

The use of iPAAG offers persistent benefits and safety through 52 weeks.