Joint prosthesis
First Claim
1. Hip-joint prosthesis comprising a cup member for placement in an articulating relation in an acetabulum of the pelvis, said cup member having a continuously smooth outer spherical surface and an inner spherical cavity which communicates with the outside through an opening, a femoral insert including a stem for insertion into the femoral bone after removal of the epiphysis thereof and a spheroidal head engaging said spherical cavity through said opening and articulated therein, wherein according to the improvement said spherical cavity is eccentrically located with respect to the outer surface of the cup member so as to be displaced in a direction diametrically opposite to said opening.
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Accused Products
Abstract
A hip joint prosthesis which comprises a cup member for placement in the acetabulum and configurated externally after a substantially spherical surface and internally to form a cavity for snap insertion on the spheroidal head of a stem to which it articulated and which is positioned in medullar cavity of the thigh bone after removal of the thigh bone epiphysis. The pivot center of said spheroidal head of the stem within the cavity of said cup member is located between the center and the spherical outer surface of the cup.
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Citations
4 Claims
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1. Hip-joint prosthesis comprising a cup member for placement in an articulating relation in an acetabulum of the pelvis, said cup member having a continuously smooth outer spherical surface and an inner spherical cavity which communicates with the outside through an opening, a femoral insert including a stem for insertion into the femoral bone after removal of the epiphysis thereof and a spheroidal head engaging said spherical cavity through said opening and articulated therein, wherein according to the improvement said spherical cavity is eccentrically located with respect to the outer surface of the cup member so as to be displaced in a direction diametrically opposite to said opening.
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2. Hip-joint prosthesis as defined in claim 1 wherein said opening has an inner frusto-conical surface that diverges in a direction outwardly from said cavity.
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3. Hip-joint prosthesis as defined in claim 2 wherein at the connection area of said spheroidal head to the stem, said stem has a lesser cross-section dimension than that of said opening.
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4. Hip-joint prosthesis as defined in claim 2 wherein said cup member has a rotation symmetry about an axis passing through the center of said opening and the centers of said outer surface and inner cavity, the center of said cavity being located on said axis between the outer surface and the center thereof.
Specification