Acetabular prosthesis and corresponding method for production and assembly

Patent metadata

Field	Value
Publication number	US-10092406-B2
Application number	US-201314438602-A
Country	US
Kind code	B2
Filing date	Oct 24, 2013
Priority date	Oct 24, 2012
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

Acetabular prosthesis comprising an acetabular cup, defining a coupling cavity, and an insert, able to be inserted inside the coupling cavity. The acetabular cup and the insert have a common coupling axis and comprise respective clamping means for their reciprocal clamping in an assembled condition.

First claim

The invention claimed is:

1. Acetabular prosthesis comprising:
an acetabular cup comprising an internal surface defining a coupling cavity and having a largest internal diameter,
an insert able to be inserted inside said coupling cavity and comprising an external surface having a largest external diameter measured when in a disassembled condition,
said acetabular cup and said insert having a common coupling axis and comprising respective clamping means for their reciprocal clamping in an assembled condition, wherein in the disassembled condition the largest internal diameter of the acetabular cup is less than the largest external diameter of said insert, and when in the assembled condition with the largest external diameter of the insert disposed within the acetabular cup the largest external diameter of said insert is equal to the largest internal diameter of the acetabular cup, wherein the internal diameter of the acetabular cup is considered in correspondence to a coupling plane between the acetabular cup and the insert defined along said coupling axis, wherein furthermore said clamping means comprise:
a first clamping surface made on said internal surface of said acetabular cup,
a second clamping surface made on said external surface of said insert, and cooperating with said first clamping surface,
wherein said second clamping surface includes the largest external diameter of said insert,
said first clamping surface and said second clamping surface having a truncated cone shape with an inclination different from each other with respect to said coupling axis, so as to obtain a conical coupling between said insert and said acetabular cup, with continuous but variable interference relative to said coupling axis; and
wherein the largest external diameter of the insert is coincident with a maximum interference between the insert and the acetabular cup.

2. Acetabular prosthesis as in claim 1 , wherein said variable interference, during use, is maximum in proximity to the maximum diameters of the cones, and minimum in proximity to the minimum diameters of the cones defining said first clamping surface and said second clamping surface, and further wherein, when in the assembled condition, the largest external diameter of said insert is coincident with a maximum interference and is disposed within the acetabular cup.

3. Acetabular prosthesis as in claim 1 , wherein said first clamping surface has an inclination less than an inclination of said second clamping surface.

4. Acetabular prosthesis as in claim 1 , wherein at least one of either said acetabular cup and said insert is made of ceramic material.

5. Acetabular prosthesis as in claim 1 , wherein said acetabular cup is shaped so as to comprise a through aperture in correspondence to a polar region thereof.

6. Acetabular prosthesis as in claim 5 , wherein said insert is shaped so as to comprise, in a polar region thereof, a centering element able to be inserted inside said through aperture.

7. Acetabular prosthesis as in claim 1 , wherein said acetabular cup comprises a plurality of recesses able to position said acetabular prosthesis in an acetabular seating.

8. Acetabular prosthesis as in claim 1 , wherein said acetabular cup comprises a trabecular reticular structure.

9. Acetabular prosthesis as in claim 8 , wherein the trabecular reticular structure constitutes all or part of the acetabular cup.

10. Acetabular prosthesis as in claim 8 , wherein at least part of the trabecular reticular structure is formed, without a break in continuity, by one or more models of a plurality of geometric meshes which are repeated in space on all the trabecular reticular structure, and have a cellular geometry with open and contiguous elementary cells, so as to define a plurality of polygons, with non-coplanar vertexes, with a spatial development delimiting cavities.

11. Acetabular prosthesis as in claim 8 , wherein the trabecular reticular structure is obtained using Electronic Beam Melting (EBM) or Selective Laser Melting (SLM).

12. Method for assembling the acetabular prosthesis as in claim 1 , comprising:
providing the acetabular cup,
providing the insert,
coupling the acetabular and the insert along the common coupling axis and reciprocally clamping said acetabular cup and said insert in the assembled condition by means of the respective clamping means,
providing the first clamping surface,
providing the second clamping surface,
obtaining the conical coupling between said insert and said acetabular cup, with variable interference along said coupling axis.

13. Method as in claim 12 , wherein it comprises at least a step in which said acetabular cup is gripped by elastic gripping means in correspondence to a through aperture, a step in which said insert is positioned on a support and centering element, a step in which the elastic gripping means are moved and said acetabular cup is coupled through variable interference with said insert, making said first clamping surface and said second clamping surface cooperate with each other, and a step in which said elastic gripping means release said acetabular cup coupled with said insert.

14. Method as in claim 13 , wherein it comprises a preliminary step of aligning and centering said elastic gripping means and said insert positioned on said support and centering element, moving said elastic gripping means downward.

15. Method as in claim 14 , wherein, after the alignment and centering of said elastic gripping means and said insert, said elastic gripping means are lifted, said insert is removed from the support and centering element, said acetabular cup is placed on the support and centering element, the elastic gripping means are moved downward to grip the acetabular cup, the elastic gripping means associated with the acetabular cup are lifted and the insert is again positioned on the support and centering element in order to proceed with the conical coupling.

16. Method as in claim 13 , wherein the assembly is obtained by applying a thermal load, or mechanically, or a combination of application of a thermal load and mechanical assembly.

17. Acetabular prosthesis as in claim 1 , wherein:
the acetabular cup includes an external surface having an external ring formed adjacent an equatorial band and in proximity to the first and second clamping surfaces and the coupling plane; and
wherein the external ring includes a height, and wherein an overall rigidity of the acetabular cup can be increased by increasing the height of the external ring.

18. Acetabular prosthesis as in claim 1 , wherein:
the largest external diameter of the insert is in direct contact with the largest internal diameter of the acetabular cup;
the acetabular cup has a polar region having a cylindrical through aperture; and
the insert includes a polar region having a cylindrical peg sized for insertion in the cylindrical through aperture.

19. Acetabular prosthesis comprising:
an acetabular cup comprising an internal surface defining a coupling cavity, the coupling cavity of the acetabular cup having a largest internal diameter;
an insert sized for insertion inside the coupling cavity and comprising an external surface and having a largest external diameter measured when in a disassembled condition;
the acetabular cup and the insert arranged for clamping to one another in an assembled condition and along a common coupling axis;
the insert and the acetabular cup arranged so that, in the disassembled condition, the largest internal diameter of the coupling cavity of the acetabul

Assignees

• Limacorporate Spa

Inventors

• Pressacco Michele

Classifications

• A61F2002/305

  Snap connection · CPC title

• Y10T29/49959

  Nonresilient fastener · CPC title

• A61F2002/30484

  Mechanically expandable devices located on the first prosthetic part for locking into or onto the second prosthetic part · CPC title

• A61F2/30771

  applied in original prostheses, e.g. holes or grooves · CPC title

• A61F2002/30838

  Microstructures · CPC title