Gavín C, Blanco FJ, Pablos JL, et al. - Whether a single injection of a new formulation of hyaluronic acid (MPS-HA2%) has efficacy and safety in the treatment of patients with symptomatic knee osteoarthritis, was evaluated in this prospective, single-arm, multicentre, open-label study with 12 months’ follow-up. A single injection of MPS-HA2% was given to patients (n = 101) with Kellgren–Lawrence 2– 3 and visual analogue scale pain scores of ≥ 40–< 80 mm. At 12 months, mean decrease in pain was noted to be 37.7%; improvement by 36.5% was evident in the total WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score and pain, stiffness and physical function subscores returned improvements of 32.1%, 34.1% and 32.7%, respectively. Findings of this not controlled trial showed that a single intra-articular injection of MPS-HA2% was effective 12 months after the procedure in the majority of the patients. This treatment showed optimal tolerability and optimal safety.