Prosthetic joint with articulating surface layers comprising ADLC

Abstract

The prosthetic joint has at least two members having each a cooperating articulating surface layer on a substrate material. At least one of said articulating surface layers comprises amorphous diamond-like carbon; or Titanium Nitrate (TiN) on a bonding layer bonded to the substrate material. The prosthetic joint provides a reduction of the number of wear debris and shows enhanced dry run properties.

Claims

1. An intervertebral implant comprising: an upper apposition member including an upper terminal surface sized and configured to abut a first vertebra, a lower surface opposite the upper terminal surface, and a first recess that extends into the lower surface; a lower apposition member including a lower terminal surface sized and configured to abut a second vertebra, an upper surface opposite the lower terminal surface, and a second recess that extends into the upper surface; a first substrate coupled to the upper apposition member, the first substrate including a first curved surface; an articulating surface layer and a bonding layer positioned between the articulating surface layer and the first curved surface, the articulating surface layer including a multi-layer composite, wherein the multi-layer composite includes a layer consisting of titanium and a layer consisting of titanium nitride adjacent the layer consisting of titanium; and a second substrate coupled to the lower apposition member, the second substrate including a second curved surface configured to movably contact the first curved surface so that the upper apposition member is moveable with respect to the lower apposition member.

2. The intervertebral implant of claim 1, wherein the articulating surface layer is a first articulating surface layer, the bonding layer is a first bonding layer, and the multi-layer composite is a first multi-layer composite; the intervertebral implant further comprising: a second articulating surface layer and a second bonding layer positioned between the second articulating surface layer and the second curved surface, the second articulating surface layer including a second multi-layer composite, wherein the second multi-layer composite includes a layer of titanium and a layer of titanium nitride adjacent the layer of titanium.

3. The intervertebral implant of claim 2, wherein the layer consisting of titanium is a first layer of titanium, the layer consisting of titanium nitride is a first layer of titanium nitride, and the first multi-layer composite includes a second layer of titanium and a second layer of titanium nitride adjacent the second layer of titanium.

4. The intervertebral implant of claim 3, wherein the second layer of titanium nitride is adjacent to the first layer of titanium.

5. The intervertebral implant of claim 2, wherein the first bonding layer comprises Niobium, Silizium, Tantalum or Gold.

6. The intervertebral implant of claim 5, wherein the second bonding layer comprises Niobium, Silizium, Tantalum or Gold.

7. The intervertebral implant of claim 1, wherein the first curved surface is concave, and the second curved surface is convex.

8. The intervertebral implant of claim 1, wherein the first curved surface is spherical.

9. The intervertebral implant of claim 8, wherein the second curved surface is spherical.

10. The intervertebral implant of claim 1, further comprising a joint member that is configured to be coupled to the upper apposition member, the joint member including the first substrate.

Description

A BRIEF DESCRIPTION OF THE DRAWINGS

(1) Several embodiments of the invention will be described in the following by way of example and with reference to the accompanying drawings in which:

(2) FIG. 1 shows a perspective view of the key functional members of a prosthetic joint according to the invention;

(3) FIG. 2 shows a perspective view of the key functional members of another prosthetic joint according to the invention;

(4) FIG. 3 shows a perspective view of the key functional members of yet another prosthetic joint according to the invention;

(5) FIG. 4 shows a cross section of the prosthetic joint of FIG. 3;

(6) FIG. 5 shows an exploded view of an embodiment of the prosthetic joint according to the invention; and

(7) FIG. 6 shows a cross section of the embodiment of FIG. 5.

(8) FIG. 1 schematically illustrates the key functional members of a prosthetic joint 1 according to the invention. The prosthetic joint 1 is configured as a uniaxial joint having an axis of rotation 4, schematizing e.g. a hinged knee prosthesis. The prosthetic joint 1 essentially comprises a first member 2 with a channel 7 coaxially penetrating the first member 2 and a second member 3 which is configured as an articular shaft 9. The first and second members 2;3 each are provided with an articulating surface layer 10;11 and a bonding layer 12;13 between the articulating surface layer 10;11 and the peripheral wall 8 of the channel 7, respectively the cylindrical surface of the articular shaft 9. The configuration of the prosthetic joint 1 with a convex sliding surface 29 at the articular shaft 9 and a concave sliding surface 30 at the peripheral wall 8 of the channel 7 solely permit a sliding relative motion between the first and second member 2;3.

(9) FIGS. 2 to 4 schematically illustrate the key functional members of a further prosthetic joint 1 according to the invention, for example of a knee joint prosthesis of the surface replacement type. The embodiments in FIGS. 2 to 4 differ from the one shown in FIG. 1 solely in a plane (FIG. 4) respectively concave (FIGS. 5 and 6) configuration of the concave sliding surface 30 of the first member 2 and an articular shaft 9 having a circular cross section, whereby the radius of curvature of the concave sliding surface 30 of the first member 2 is greater than the radius of the convex sliding surface 29 of the articular shaft 9. This configuration of the first and second member 2;3 permits a superimposed sliding and rolling motion of the first and second member 2;3 relative to each other.

(10) FIGS. 5 and 6 illustrate an embodiment of the prosthetic joint 1 in the form of an intervertebral implant 14, particularly an intervertebral disc prosthesis comprising an upper apposition member 15, a lower apposition member 16 and a ball-and-socket joint 22 articulatedly connecting said upper and lower apposition member 15;16. Opposite the ball-and-socket joint 22 the upper and lower apposition member 15;16 comprise an upper terminal surface 17, respectively a lower terminal surface 18, whereby said upper terminal surface 17 is configured for abutting the base plate of a first intervertebral body contacting the intervertebral implant 14 on top and said lower terminal surface 18 is configured for abutting the cover plate of a second intervertebral body contacting the intervertebral implant 14 at the bottom. The ball-and-socket joint 22 is a two-piece member having a spherical convex joint member 23, the convex sliding surface 29 of which is configured as a spherical cap with the central axis 19 of the intervertebral implant 14 intersecting the spherical cap at its apex. At the rear end 25 of the convex joint member 23 a first cylindrical section 31 is provided by means of which the convex joint member 23 may be fit into a corresponding first recess 27 in the intermediate surface 21 of the lower apposition member 16, which is arranged opposite to the lower terminal surface 18. Analogously, the rear end 26 of the concave joint member 24 comprises a second cylindrical section 32 by means of which the concave joint member 24 may be fit into a corresponding second recess 28 in the intermediate surface 20 of the upper apposition member 15 which is arranged opposite the upper terminal surface 17.

(11) In this exemplary embodiment the first and second bonding layers 12;13 are metallic, have a thickness between 3 nanometer and 6 micrometer and are fixed at the respective first and second substrates 33;34 of the corresponding convex and concave joint members 23;24 by means of chemical vapor deposition technique whereas the first and second articulating surfaces 10;11 have a thickness between 2 and 30 micrometer and are applied by means of a plasma assisted chemical vapor deposition process.

(12) The convex sliding surface 29 and the concave sliding surface 30 have the same radius, which permits a sliding motion of the convex sliding surface 29 relative to the concave sliding surface 30 when the ball-and-socket joint 22 is bent or stretched. Analogously, a sliding motion between the convex and concave sliding surface 29;30 is performed when the first and second member 2;3 of the prosthetic joint rotate relative to each other about the central axis 19.