In this multicenter, randomized, double-blind, three-arm study, the investigator propose to evaluate the safety and efficacy at Day0, Month1, Month3 and Month6 of a single intra-articular injection of a combination RM-PRP-XLHA (experimental treatment: combination of cross-linked HA and PRP obtained with the RegenMatrix medical device) against Hylan G-F 20 (reference treatment) and placebo for the treatment of moderate to severe knee osteoarthritis.~The symptomatic benefit will be evaluated in terms of pain reduction and improvement of patient's quality of life. The functional benefit of the treatment will also be evaluated, on a reduced number of participants, by a gait analysis, performed only in the coordinating centre.~The medical device RegenMatrix is an adaptation of the medical device Cellular Matrix (certified since 2013,CE2797). It differs from the latter only for by presence of cross-linked HA instead of linear HA, and is therefore particularly suitable for the treatment of moderate to severe knee osteoarthritis.
In this clinical trial the investigator assess the safety and efficacy of a single injection of a combination of cross-linked hyaluronic acid (HA) with autologous platelet-rich plasma (PRP) obtained with the RegenMatrix medical device to improve symptoms of moderate to severe knee osteoarthitis (grade III-IV Kellgren-Lawrence).