1. An implant (1； 100) of a joint for implantation inside the bone, comprising: a rod (10) having a proximal section (11) and a distal section (15)； at least two grooves (12), which essentially extend in the longitudinal the direction of said rod (10)； a first coating (14) at least partially covering the surface (14) of said elongated grooves (12)； a ridge-shaped protrusion (13), wherein said ridge-shaped protrusion is formed between adjacent grooves (12) and has an apical surface (13a)； wherein said apical surface (13a) has an average surface roughness that is lower than the average surface roughness of the first coating (14). 2. An implant (1； 100) according to claim 1, wherein the grooves (12) have a depth of at least 1 mm, preferably at least 2 mm, and even more preferably at least 3 mm. An implant (1； 100) according to claim 1 or 2, wherein said comb-shaped protrusion has such a width that the ratio of the width of the groove (12) to the width of the comb-shaped protrusion (13) is from 0.5 to 5, preferably from 1.5 up to 4.4. An implant (1； 100) according to claim 1 or 2, in which at least one of the grooves (12) is made with the ability to open in its longitudinal direction near at least one of the ends - proximal or distal. An implant (1； 100) according to claim 1 or 2, in which the cross section of at least one of the grooves (12) is constant and / or increases in width near the apical surface (13a) of the ridge-shaped protrusion (13) .6. An implant (1； 100) according to claim 1 or 2, wherein the apical surface (13a) of the ridge-shaped protrusion (13) has an average surface roughness of at least 2.5 μm. The implant (1； 100) according to claim 1 or 2, in which the first coating (14) of the grooves (12) is a titanium-plasma coating,1. Имплантат (1； 100) сустава для вживления внутрь кости, содержащий:стержень (10), имеющий проксимальный участок (11) и дистальный участок (15)；по меньшей мере, две бороздки (12), которые по существу проходят в продольном направле
