 5. The use of botulinum toxin BoNT-A could thus represents an interesting alternative. BoNT-A is habitually used by intra-muscular injection for its myorelaxant effect in the management of painful reactive periarticular muscle contractures. However, BoNT-A has also antalgic activity independently of the myorelaxant effect. This allows explaining in part the antalgic effect of intra-articular BoNT-A injection. In the literature, six randomized controlled studies RCS have compared BoNT-A and intra-articular injections of corticosteroids, hyaluronic acid, or placebo. Only two RCS concerned knee osteoarthritis and compared BoNT-A to corticosteroids and a placebo, respectively, with a significant antalgic effect only in the groups treated with BoNT-A. No study has compared yet the intra-articular injection of BoNT-A to the viscosupplementation by HA in knee osteoarthritis and this is the aim of this trial. 