A knee orthosis includes two parts, upper and lower, each provided with at least one attachment means linking supporting parts, suitable for attaching said upper and lower parts respectively to a thigh and to a leg. Both parts are linked via bi-centric articulation means suitable for enabling each of said parts to pivot about a common axis between the ends of the supporting parts and an intermediate part forming a connection rod. A cord linking links the common axis between the connection rod connecting an articulation means to the upper portion of the orthosis, with the distal end of an arm forming one of the supporting parts of the lower portion of the orthosis.
