The invention relates to a knit having barbs protruding outwards from both faces obtained by knitting yarns of biocompatible material in guide-bars B2, B3 and B4 of a knitting machine, wherein the knitting patterns followed by guide-bars B2 and B3 involve at least two needles and produce an arrangement of yarns defining two faces of the knit, the knitting pattern followed by guide-bar B4 making stitches generating loops protruding outwards from each of the faces of the knit, guide-bar B4 being threaded with a hot-melt monofilament yarn, heat-setting the knit, forming barbs by cutting the loops via melting.