Abstract: The invention relates to a cotyloid component of a hip prosthesis, said cotyloid component being hollow and in the form of a cup whose outer part has a thread allowing it to be fixed in the iliac bone, said thread being a discontinuous self-cutting double thread (20, 21), and said cotyloid component having a flattened upper pole (1), a coating that promotes osseointegration on its outer face (10), and a concave, substantially hemispherical and polished inner surface (11), characterized in that: (a) the pitch of the threads (20, 21) decreases from the upper pole (1) towards the equatorial periphery (3) of the cotyloid component, (b) the thicknesses of the threads (20, 21) increase from the upper pole (1) of the cotyloid component towards its periphery (3), (c) the crest of the threads (20, 21) is sharp towards the pole (1) of the cotyloid component and rounded or substantially trapezoidal towards the equatorial periphery (3) of the cotyloid component.

Abstract: Acetabular insert comprising a spherical head arranged at one end of a medullary stem and mounted with articulation inside a core, which is itself mounted with articulation inside an acetabular component. The spherical head is made of zirconia and the core comprises an inner cup consisting of an alumina cup on which is immobilized a polyethylene cup overmolded on the alumina cup. In addition, the spherical head is configured so as to be able to be engaged without stress in the cup and be retained directly and exclusively by the latter.