Prosthesis for restoring motion in an appendage or spinal joint and an intervertebral spacer
First Claim
1. A motion restoring prosthesis to be interposed between the ends of mammalian bones adjoining a natural appendage or spinal joint to provide articulation therebetween comprising:
- two components, each component defining an outer surface for attachment to a respect bone end and an articulating surface for engaging the articulating surface of the other component;
at least one of the components having an inner and outer section, the inner section defining the articulating surface and being formed of a primary, relatively hard, stiff material having a first flexural modulus, the outer section defining a bone facing surface to be attached to one of the bone ends and formed of a secondary softer material having a second flexural modulus, the first flexural modulus being greater than the second flexural modulus, the outer section functioning as a stress softening material to more evenly distribute the forces from the articulating surfaces to the associated bone end, wherein the bone facing surface of said at least one component has been roughened and/or made uneven to enhance an attachment of adjacent bone and covered with a thin coating of Ti within a range of 0.5 to 15 microns in thickness to enable bone-on growth while maintaining an appropriate distribution of forces through the thin coating of Ti to permit the stress shielding characteristic of the coated secondary softer material to be operative.
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Accused Products
Abstract
A motion restoring prosthesis to be interposed between the ends of two bones adjoining a mammalian appendage or spinal joint is formed of two components with the components having inner cooperating articulating surfaces and outer bone engaging surfaces. At least one of the components has an inner section made of relatively hard, stiff material defining one or the articulating surfaces and an outer section made of a softer material defining the bone engaging surface. The softer material having a hardness/stiffness characteristic compatible with the bone to reduce stress shielding and more evenly distribute the forces from the articulating surfaces to the associate bone interface.
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Citations
20 Claims
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1. A motion restoring prosthesis to be interposed between the ends of mammalian bones adjoining a natural appendage or spinal joint to provide articulation therebetween comprising:
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two components, each component defining an outer surface for attachment to a respect bone end and an articulating surface for engaging the articulating surface of the other component; at least one of the components having an inner and outer section, the inner section defining the articulating surface and being formed of a primary, relatively hard, stiff material having a first flexural modulus, the outer section defining a bone facing surface to be attached to one of the bone ends and formed of a secondary softer material having a second flexural modulus, the first flexural modulus being greater than the second flexural modulus, the outer section functioning as a stress softening material to more evenly distribute the forces from the articulating surfaces to the associated bone end, wherein the bone facing surface of said at least one component has been roughened and/or made uneven to enhance an attachment of adjacent bone and covered with a thin coating of Ti within a range of 0.5 to 15 microns in thickness to enable bone-on growth while maintaining an appropriate distribution of forces through the thin coating of Ti to permit the stress shielding characteristic of the coated secondary softer material to be operative. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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- 12. A motion restoring prosthesis or intervertebral spacer including a bone buttressing material having a GPa flexural modulus of about 60 or less and defining a bone buttressing surface, the bone buttressing surface functioning as a stress softening material, said surface being roughened or made uneven when abutted against the bone, to enhance an attachment of adjacent bone and covered with a thin coating of Ti within a range of 0.5 to 15 microns in thickness to enable bone-on growth while maintaining an appropriate distribution of force through the thin coating of Ti to permit the stress shielding characteristics of the bone buttressing surface to be operative.
- 17. An intervertebral spacer for replacing a natural disc, the spacer being formed of a material which has a GPa flexural modulus within the range of about 4-40 and defining opposing bone buttressing surfaces which are roughened or made uneven to enhance an attachment of adjacent bone and coated with a thin micron coating of a titanium bone-on growth enhancing material within a range of 0.5 to 15 microns in thickness which does not adversely affect bone stress transfer characteristics of the bone buttressing material.
Specification