<p>The prosthesis has a shank (1) with a broad upper end (2) tapering towards its tip (12), and is equipped with a distal centering element (14) of a resorbable material. The shank also has a wedging projection (10) on its rear surface to engage with the rear inner surface of the femur. From a sagittal viewpoint the projection has a radius of curvature which is equivalent to approximately one third of the radius of curvature of the shank's rear face. The centering element (14) is in the form of a ring with an inner diameter sized so that it fits at a point 15 +/- 2 mm above the tip of the shank. Its aperture tapers at an angle of 15 +/- 2 degrees, and it is 5 +/- 1 mm thick. The ring's outer diameter is between 12 and 32 mm, and it has at least one peripheral recess.</p>
