Abstract: Articular prosthetic device which comprises: a half-shell having an inner surface and an insert having an outer surface, the inner surface of the half-shell and the outer surface of the insert being shaped so that the insert is retained within the half-shell when it is pushed therein, by applying a force thereto directed along an axis of impaction, with surface contact between the two mating surfaces, the outer surface of the insert comprising a plurality of sections, each section forming, in cross-section, with the impaction axis, an internal angle of less than 12.degree., the inner surface of the half-shell comprising portions mating with the sections and forming in cross-section, with the impaction axis, an external angle substantially equal to the internal angle.

Abstract: The prosthesis is provided with a medial narrow side which extends on a hyperbola from a conical distal section to a boundary plane at which the blade is connected to the neck of the prosthesis. The vertex of the hyperbola is disposed at the point of intersection of the curved medial narrow side with the neck and a tangent to the hyperbola at the point of intersection with the distal section is one-half the conical angle of the blade.

Abstract: The prosthesis has a blade with a roof-ridge shaped shoulder at the proximal end adjacent to the neck. In addition, a bore is disposed in the shoulder on a medial plane so that a hook-shaped instrument can be inserted in to the bore from a direction of the neck. Movement and alignment of the blade via the insertion instrument is performed in the direction of the longitudinal axis of the blade.