Abstract: A cotyloid implant for a hip prosthesis, includes a first type of insert (2) with a spherical internal cavity (2a), for the mounting of a hemispherical core (4) with a capacity for mobility which has an internal cavity (4a) for co-operation with articulation with a femoral head, a second type of insert with an internal cavity for cooperation with a femoral head with articulation, characterized in that the center of rotation of the femoral head is different from the axis of rotation of the first type of insert (2) and/or of the second type of insert.

Abstract: A modular assembly for a femoral prosthesis comprises a femoral prosthetic implant forming a spindle of elongate and tapered shape and a one-piece neck. The implant consists of a diaphyseal lower part and a metaphyseal upper part having a flat face delimited by an outer edge and in which a cavity is formed. The neck is formed of a tenon having a shape corresponding to the cavity, said tenon being fitted into the cavity along an insertion axis YY perpendicular to the flat face and a rod provided with an interface for fixing a cup that is to be inserted into the acetabulum of the hip bone. The rod is provided with a tongue which protrudes parallel to the flat face in a radial direction with respect to the insertion axis and directed towards the interior of the obtuse salient angle, at a distance from the flat face of between 0.3 mm and 1.