Effect of a Single-Shot of a High-Density Viscoelastic Solution of Hyaluronic Acid in Patients with Symptomatic Primary Knee Osteoarthritis: The No-Dolor Study

Background: Pronolis®HD mono 2.5% is a novel, one-shot, high-density sterile viscoelastic solution, recently available in Spain, which contains a high amount of intermediate molecular weight hyaluronic acid (HA), highly concentrated (120 mg in 4.8 mL solution: 2.5%). The objective of the study was to analyze the efficacy and safety of this treatment in symptomatic primary knee osteoarthritis (OA). Methods This observational, prospective, multicenter, single-cohort study involved 166 patients with knee OA treated with a single-shot of Pronolis®HD mono 2.5% and followed up as many as 24 weeks. Results Compared with baseline, the score of the Western Ontario and McMaster Universities Arthritis Osteoarthritis Index (WOMAC) pain subscale significantly reduced at the 12-week visit (primary endpoint, median: 9 interquartile range [IQR]: 7-11 versus median: 4; IQR: 2-6). The percentage of patients achieving >50% improvement in the pain subscale increased progressively from 37.9% (at 2 weeks) to 66.0% (at 24 weeks). Similarly, WOMAC scores for pain on movement, stiffness subscale, and functional capacity subscale showed significant reductions at the 12-week visit which were maintained up to the 24-week visit. The EuroQol visual analog scale score significantly increased after 12 weeks (median: 60 versus 70). The need for rescue medication (analgesics/nonsteroidal anti-inflammatory drugs) also significantly decreased in all post-injection visits. Three patients (1.6%) reported local adverse events (joint swelling) of mild intensity. Conclusions In conclusion, a single intra-articular injection of the high-density viscoelastic gel of HA is effective and safe for the relief of symptoms in patients with knee OA. Trial registration: ClinicalTrial# NCT04196764