Ancillary tool and method for positioning a prosthetic acetabulum of a hip prosthesis

An ancillary tool and method for manipulating and implanting a prosthetic acetabulum including a tool provided, adjacent a distal part, with a head for interacting with an endpiece that is used for gripping the acetabulum and, in its proximal part, with a surface for application of a force along the handle. The endpiece is preferably removably connected to the distal end of the handle. The endpiece includes an elastically deformable ring having an outer face for expanding radially outwardly to initially grip the acetabulum and an opposite face for interaction with the head of the handle, such that upon a force being applied to drive the head into a cavity of the endpiece, the ring is radially expanded to expand the acetabulum in place after which the ring elastically returns to its original shape as the head is removed from the cavity.