The bolt comprises a barrel (10) which is generally cylindrical and capable of engaging in a hole formed in the cortical wall, and a screw (2) capable of being driven into an axial bore of the barrel in order to expand the latter radially and block it in the hole, the prosthesis being passed around the barrel and pressed against the bone by a collar (11) forming a cap at the end of the barrel. The screw, the barrel and the collar are made of physiologically acceptable metal. The barrel (10) and the collar (11) are made in one piece. The bore (17) is tapped to the pitch of the screw (2) from the collar (11) to a median cross-section (13), beyond which it narrows (12) to a diameter smaller than the diameter at the base of the thread of the screw (2), while the latter has a point (21) in the shape of a tapered cone. The barrel has slots (15) which extend in planes passing through the axis from an end edge (12a) of the barrel (10), opposite the collar (11), as far as an intermediate cross-section (17) between the median cross-section (13) and the collar (11).