Orthopaedic Device and Procedure to Realize Such a Device

Procedure to realize an orthopaedic device (1) for the movable connection of a first and a second bony segment (4, 5) of an organic apparatus to substitute or to cooperate with a natural articulation (2), characterized by the fact to comprise the phases of:

• finding experimentally the axodes of the real spatial motion of the said articulation (2);
• finding the centrodes (σ1, σ2) of a planar relative motion or the axodes of a spherical relative motion which represent an approximation of the said real spatial motion;
• associating a first working surface (9), defined as a portion of a first ruled surface with a curvilinear directrix, to a said first bony segment (4);
• associating a second working surface (10), defined as a portion of a second ruled surface with a curvilinear directrix, to a said second bony segment (5);
• the directrices of the said first and second ruled surface being the said centrodes of motion;
• constraining the said first and second working surfaces (9, 10) by means of connecting elements (8) to allow the said first surface (9) and the said second surface (10) to roll one over the other.

Procedure to realize an orthopaedic device (1) for the mobile connection of a first and a second bony segment (4, 5) belonging to an organic apparatus for replacing or collaborating with a natural articulation (2), characterized by the fact to comprise the phases of:

• simulating the said natural articulation (2) by a linkage (13) substantially equivalent to the said natural articulation (2);
• finding the centrode (σ1, σ2) of the relative motion of a first link (4′) and a second link (5′) of the said linkage (13), called first link (4′) being the corresponding of the said first bony segment (4) of the said linkage (13) and called second link (5′) being the corresponding of the said second bony segment (5) of the said linkage (13);
• relating a first working surface (9), defined as a portion of a first ruled surface with a curvilinear directrix, to the said first bony segment (4);
• relating a second working surface (10), defined as a portion of a second ruled surface with a curvilinear directrix, to the said second bony segment (5);
• the directrices of the said first and second ruled surfaces being the centrodes (σ1, σ2) of motion;
• constraining the said first and second working surfaces (9, 10) by means of connecting elements (8) to allow the above said first surface (9) and the above said second surface (10) to roll one over the other.