The aim of this study was to provide with the first kinetic data regarding biomarkers in painful knee osteoarthritis patients treated with a new reticulated hyaluronic acid. The effects of the treatment were compared to those of saline solution. The primary endpoint was a specific osteoarthritis biomarker, Coll2-1. The secondary endpoints were the effects of the treatment or placebo on other biomarkers of osteoarthritis, its clinical efficacy and tolerance