Method and apparatus for providing resorbable fixation of press-fit implants
View Patent ↗A press-fit prosthesis for replacing a portion of a bone. The prosthesis can comprise a first side and a second side opposite the first side. The second side can be operable to engage the bone. The prosthesis can include at least one resorbable fixation member coupled to the second side such that the at least one resorbable fixation member does not extend through to the first side. The at least one resorbable fixation member can be coupled offset from a center of the second side. The at least one resorbable fixation member can substantially resist movement of the prosthesis relative to the bone. The at least one resorbable fixation member can resorb at a rate that enables bone in-growth to fixedly couple the prothesis to the bone.
1. A press-fit prosthesis for replacing a portion of a bone comprising:
a tibial tray devoid of apertures passing there through having:
a medial portion;
a lateral portion;
a center portion between the medial portion and the lateral portion;
a first side; and
a second side opposite the first side, the second side operable to engage the bone; and
a pair of first resorbable fixation members coupled to the second side at the medial portion and a pair of second resorbable fixation members coupled to the second side at the lateral portion, the resorbable fixation members do not extend through to the first side, the resorbable fixation members are coupled offset from the center portion of the second side, the resorbable fixation members substantially resist movement of the prosthesis relative to the bone;
wherein the resorbable fixation members resorb at a rate that enables bone in-growth to fixedly couple the prosthesis to the bone;
wherein the center portion is devoid of a fixation member; and
wherein the second side includes a roughened portion confined to an area immediately surrounding each of the resorbable fixation members, each of the roughened portions are separate and spaced apart from one another.
2. The prosthesis of claim 1 , wherein the first side defines a bearing engaging surface that forms a barrier that continuously extends from the first side to the second side and the second side comprises a bone engaging surface.
3. The prosthesis of claim 2 , wherein the bone engaging surface is selected from the group consisting of a porous metal structure, a porous metal alloy structure, a solid metal structure, a solid metal alloy structure, a porous coating, and combinations thereof.
4. The prosthesis of claim 2 , wherein the first side is without holes and the resorbable fixation members extend from only the second side.
5. The prosthesis of claim 2 , wherein the resorbable fixation members are each molded onto the bone engaging surface.
6. The prosthesis of claim 2 , further comprising:
a bearing positioned on the bearing engaging surface of the tibial tray and extending entirely across the medial portion, the center portion, and the lateral portion; and
a femoral component that articulates relative to the bearing to form a knee joint, the femoral component including a medial condyle, a lateral condyle, and a center portion that extends from the medial condyle to the lateral condyle to connect the medial condyle to the lateral condyle.
7. The prosthesis of claim 2 , wherein none of the resorbable fixation members are coupled to the center portion of the bone engaging surface.
8. The prosthesis of claim 3 , wherein the porous metal or metal alloy structure, the solid metal or metal alloy structure, and the porous coating cover less than an entirety of the bone engaging surface.
9. The prosthesis of claim 1 , wherein the resorbable fixation members each include at least one feature to enable the tibial tray to be press-fit into two bores formed in the medial side of the bone and two bores formed in the lateral side of the bone.
10. The prosthesis of claim 9 , wherein the at least one feature is selected from the group consisting of a barb, a cylinder, a cruciate form, a projection, a polygon, a cone, a disk, a sphere, and combinations thereof.
11. The prosthesis of claim 9 , wherein the bone is a tibia; and
wherein the prosthesis is press-fit into the tibia along a longitudinal axis of the tibia.
12. The prosthesis of claim 9 , wherein the at least one feature is sized to engage the plurality of bores formed in the bone such that the prosthesis does not substantially move relative to the bone.
13. The prosthesis of claim 1 , wherein the resorbable fixation members are each composed of a bio-resorbable material selected from the group consisting of a resorbable polymer, a resorbable coral structure, and combinations thereof.
14. The prosthesis of claim 1 , wherein the second side includes a plurality of coupling features in only the medial and lateral portions that are each operable to couple one of the resorbable fixation members to the tibial tray.
15. The prosthesis of claim 14 , wherein each of the coupling features include one of an annular protrusion extending from the second side, a threaded receptacle, a conical protrusion, an aperture, a notched protrusion, a rectangular protrusion, or a polygonal protrusion.
16. The prosthesis of claim 1 , wherein the roughened portion includes at least one of a porous coating, a porous layer, a collagen foam, or a ceramic layer.