Clinical effectiveness and safety of intra-articular injection of HYALGO in the management of knee osteoarthritis symptoms: A multicenter prospective study

Background: The reduced concentration of hyaluronic acid in the synovial fluid, leading to impairment of joint function and painful symptomatology during knee osteoarthritis (OA), can be restored by using injectable formulations of hyaluronic acid (HA) and chondroitin sulfate (CS), variable for relative composition, HA/CS molecular modifications, and injection protocols. The present study aims to assess the safety and performance of the intra-articular (IA) viscosupplementing agent HYALGO, a formulation combining 40 mg/mL HA (>1700 kDa) and 40 mg/mL CS, in the treatment of patients suffering from knee OA.

Methods: 74 patients affected by knee lesions classified as grade II and III according to Kellgren and Lawrence classification were prospectively recruited and treated with three HYALGO injections (2 mL) given one week apart. Visual analogue scale (VAS) pain changes were monitored at each injection and over-time at 6, 14, and 26 weeks of follow-up. Secondary endpoints were: Western Ontario McMaster University Osteoarthritis index (WOMAC), Patient's Global Assessment (PGA) score, Clinical Observer Global Assessment (COGA) score, Outcome Measures in Rheumatology Committee (OMERACT) and Osteoarthritis Research Society International (OARSI) responders rates. Patients were also assessed for changes in their ultrasound joint scores according to the criteria of the OMERACT US Task Force Group.

Results: Pain reduction was statistically significant starting from the first IA injection. Mean pain reduction from baseline to week 26 was -90.6%. At 26 weeks, WOMAC Pain was reduced by -62.7%, WOMAC Stiffness by -47.2%, WOMAC Physical Function by -54.1%; Total WOMAC by -53.8%. The VAS PGA change from baseline was -48.0 [mm] and VAS COGA -41.0 [mm]. Responders at week 26 were 78.4%. Ultrasound parameters (joint effusion, synovial thickness, and popliteal cysts) improved or remained stable from baseline to week 6.

Conclusions: Three injections of HYALGO were safe and effective to manage symptomatic knee OA, with a beneficial effect that increased progressively over time, peaking 6 months after injection.