Patent ID: 9241799
Filing Date: 2016-01-26
CPC Classification: A61F,F04C

Claim Text:
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 an 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 an 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 (i) 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, (ii) 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, and (iii) one of the first and second features comprises at least one annular or semi-annular groove and the other of the first and second 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 first insert with respect to the acetabular shell about only the first axis, and 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, wherein the at least one semi-annular groove of the third feature or fourth feature includes two semi-annular grooves centered around the second axis and disposed on opposite sides of the first insert or the second insert and the at least one semi-annular projection of the third feature or the fourth feature includes two semi-annular projections centered around the second axis and disposed on opposite sides of the other of the first and second inserts.