Constrained mobile bearing hip assembly

Patent metadata

Field	Value
Publication number	US-9700416-B2
Application number	US-201615005583-A
Country	US
Kind code	B2
Filing date	Jan 25, 2016
Priority date	Jun 21, 2012
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

An acetabular hip implant includes an acetabular shell component having a first feature and a first insert having a second feature that cooperates with the first feature of the acetabular shell component and further includes a third feature. The implant further includes a second insert having a fourth feature that cooperates with the third feature of the first insert and further includes a fifth feature. A femoral head component includes a sixth feature that cooperates with the fifth feature. Interaction between the first and second features, between the third and fourth features, and between the fifth and sixth features mechanically constrains the acetabular hip implant to prevent dislocation of the femoral head during rotation.

First claim

The invention claimed is:

1. An acetabular hip implant, comprising:
an acetabular shell component configured to be implanted within an acetabulum of a patient, the acetabular shell having a first feature defined in its inner surface,
a first insert secured to the acetabular shell component such that an outer surface of the first insert contacts the inner surface of the acetabular shell, the first insert having a second feature defined in its outer surface which contacts the first feature defined in the inner surface of the acetabular shell such that the first insert is (i) permitted to rotate relative to the acetabular shell component about a first axis and (ii) prevented from rotating relative to the acetabular shell component about a second axis and a third axis, the first insert having a third feature defined in its inner surface,
a second insert secured to the first insert such that the outer surface of the second insert contacts the inner surface of the first insert, the second insert having a fourth feature defined in its outer surface that contacts the third feature defined in the inner surface of the first insert such that the second insert is (i) permitted to rotate relative to the first insert about the second axis and (ii) prevented from rotating relative to the first insert about the first axis and the third axis, the second insert having a fifth feature defined in its inner surface, and
a femoral head configured to be secured to a femoral stem, the femoral head being secured to the second insert such that the outer surface of the femoral head contacts the inner surface of the second insert, the femoral head having a sixth feature defined in its outer surface which contacts the fifth feature defined in the inner surface of the second insert such that the femoral head is (i) permitted to rotate relative to the second insert about the third axis and (ii) prevented from rotating relative to the second insert about the first axis and the second axis;
wherein interaction between the first and second features, between the third and fourth features, and between the fifth and sixth features mechanically constrains the acetabular hip implant to prevent dislocation of the femoral head during rotation,
wherein the first feature is different than the second feature, the third feature is different than the fourth feature, and the fifth feature is different than the sixth feature,
wherein one of the first and second features comprises a semi-circular groove and the other of the first and second features comprises a semi-circular projection that is movably secured within the semi-circular groove to permit rotation of the first insert with respect to the acetabular shell about only the first axis, and
wherein one of the fifth and sixth features comprises an annular groove and the other of the fifth and sixth features comprises an annular projection that is movably secured within the annular groove to permit rotation of the femoral head with respect to the second insert about only the third axis.

2. The acetabular hip implant of claim 1 , wherein one of the third and fourth features comprises at least one annular or semi-annular groove and the other of the third and fourth features comprises at least one annular or semi-annular projection that is movably secured within the at least one annular or semi-annular groove to permit rotation of the second insert with respect to the first insert about only the second axis.

3. The acetabular hip implant of claim 2 , wherein the at least one semi-annular groove includes two semi-annular grooves centered around the second axis and disposed on opposite sides of the first or second insert and the at least one semi-annular projection includes two semi-annular projections centered around the second axis and disposed on opposite sides of the other of the first and second inserts.

4. The acetabular hip implant of claim 1 , wherein the annular projection and the annular groove are centered around and symmetrical about the third axis.

5. The acetabular hip implant of claim 4 , wherein the annular projection and the annular groove are offset from diameters of the second insert and the femoral head.

6. The acetabular hip implant of claim 1 , wherein the first axis is orthogonal to the second axis and the third axis and the second axis is orthogonal to the third axis.

7. The acetabular hip implant of claim 1 , wherein the first feature includes two semi-circular projections disposed on opposite sides of the acetabular shell and the second feature includes two semi-circular grooves disposed on opposite sides of the first insert, and wherein the projections and grooves are centered about the first axis to allow for rotation about the first axis.

8. The acetabular hip implant of claim 1 , wherein one of the third and fourth features comprises a semi-circular groove and the other of the third and fourth features comprises a semi-circular projection that is movably secured within the semi-circular groove to permit rotation of the second insert with respect to the first insert about only the second axis.

9. The acetabular hip implant of claim 8 , wherein the third feature includes two semi-circular projections disposed on opposite sides of the first insert and the fourth feature includes two semi-circular grooves disposed on opposite sides of the second insert, and wherein the projections and grooves are centered about the second axis to allow for rotation about the second axis.

10. The acetabular hip implant of claim 1 , wherein the annular projection and the annular groove are centered around and symmetrical about the third axis and are offset from a diameter of the second insert.

11. The acetabular hip implant of claim 10 , wherein the first axis is orthogonal to the second axis and the third axis and the second axis is orthogonal to the third axis.

12. An acetabular hip implant, comprising:
an acetabular shell component configured to be implanted within an acetabulum of a patient, the acetabular shell component having a first set of projections or grooves defined within an inner surface of the acetabular shell,
a first insert having an outer surface, the first insert being secured to the acetabular shell component such that the outer surface of the first insert contacts the inner surface of the acetabular shell, the first insert having a second set of projections or grooves defined within the outer surface of the first insert and cooperating with the first set of projections or grooves defined within the inner surface of the acetabular shell such that the first insert is permitted to rotate relative to the acetabular shell component about a first axis, the first insert having a third set of projections or grooves defined within an inner surface of the first insert,
a second insert secured to the first insert such that an outer surface of the second insert contacts the inner surface of the first insert, the second insert having a fourth set of projections or grooves defined in its outer surface which cooperate with the third set of projections or grooves defined in the inner surface of the first insert such that the second insert is permitted to rotate relative to the first insert about the second axis, the second insert having a first annular projection or groove defined in its inner surface, and
a femoral head configured to be secured to a femoral stem, the femoral head being secured to the second insert such that an outer surface of the femoral head contacts the inner surface of the second insert, the femoral head having a second annular projection or groove defined in its outer surface which cooperates with the first annular projection or groove defined in the

Assignees

• Depuy Synthes Products Inc

Inventors

• Grostefon Justin D
• Block Matthew T

Classifications

• A61F2/34

  Acetabular cups · CPC title

• A61F2002/3216

  tripolar · CPC title

• A61F2002/30934

  Special articulating surfaces · CPC title

• A61F2002/30397

  Limited lateral translation of the rib within a larger groove · CPC title

• A61F2002/3208

  Bipolar or multipolar joints, e.g. having a femoral head articulating within an intermediate acetabular shell whilst said shell articulates within the natural acetabular socket or within an artificial outer shell · CPC title