The prosthesis has an element (2) provided with a pivoting stem (6) whose end (6a) is formed with a hole having diameter greater than that of a transverse pin (8), so that an annular clearance exists between the pin and a wall of the stem. The element has recesses (9) in a form of spherical cap at the hole and on side faces delimiting the cavity, and is located in a same geometric sphere. The end has a sphere shaped central portion around the hole, where diameter of the portion is slightly less than that of the sphere and thickness less than distance separating the side faces.
