Abstract: The invention relates to a system which is used to replace ball bone joints. The inventive system consists of: a bone anchoring shell (1) comprising a smooth articular surface (7) on the inner concave face thereof; a prosthesis (5) comprising a polished ball (4) and a neck (6) which is characterised in that it is smooth and slightly flared, in order to enable a wear-free low friction movement; and a mobile articular cup (3) which slides (i) on the ball (4) and the neck (6) of a prosthesis (5) and (ii) in the smooth cavity (7) of the bone anchoring shell (1) and which is characterised in that the opening (8) in said cup (3) tapers towards the center thereof, with an inside diameter (9) of equal to or less than that of the ball (4), such that the flared part adapts perfectly to the flared neck (6) in all of the respective positions of the mobile parts.

Abstract: The invention relates to a system which is used to replace ball bone joints. The inventive system consists of: a bone anchoring shell (1) comprising a smooth articular surface (7) on the inner concave face thereof; a prosthesis (5) comprising a polished ball (4) and a neck (6) which is characterised in that it is smooth and slightly flared, in order to enable a wear-free low friction movement; and a mobile articular cup (3) which slides (i) on the ball (4) and the neck (6) of a prosthesis (5) and (ii) in the smooth cavity (7) of the bone anchoring shell (1) and which is characterised in that the opening (8) in said cup (3) tapers towards the centre thereof, with an inside diameter (9) of equal to or less than that of the ball (4), such that the flared part adapts perfectly to the flared neck (6) in all of the respective positions of the mobile parts.

Abstract: A prosthesis for the knee articulation is provided which has a femoral implant having two condyles which are of convex shape, each having a variable radius, and a tibial implant having two cavities, each of which interacts with a respective one of the condyles. In its posterior region, the internal condyle has a spherical prominence which projects from the contact plane of the internal condyle and is intended to interact with a spherical cap hollowed into the posterior region of the internal cavity of the tibial implant.