Threaded cable anchor
A bone anchor for securing sutures or cables within a hole opening in a bone includes a screw element and a washer, which is separate from and independent of the screw element. The end of the cable to be secured within the bone hole opening is knotted or otherwise secured to the washer, thereby isolating the cable from the twisting of the screw element during insertion of the anchoring device into the hole opening in the bone.
1. A bone anchor, comprising a screw element having a first passageway which extends axially through said screw element from one end thereof to an opposite end thereof; a washer having a second passageway which extends axially through said washer from one end thereof to an opposite end thereof, said one end of said washer being positionable adjacent to said opposite end of said screw element such that said first and second passageways are substantially aligned and such that said screw element is rotatable independently of said washer; and a cable member attached to said washer and passing through said first and second passageways such that said cable member is not rotatable in response to the rotation of said screw element.
2. A bone anchor according to claim 1 wherein said one end of said screw element has engaging means for engaging an insertion tool.
3. A bone anchor according to claim 2 , wherein said engaging means includes a plurality of teeth arranged in a circular array on said one end of said screw element.
4. A bone anchor according to claim 3 , wherein said one end of said screw element has a castellated shape.
5. A bone anchor according to claim 1 wherein said screw element is externally threaded.
6. A bone anchor according to claim 5 , wherein said screw element is of a self-tapping type.
7. A bone anchor according to claim 5 , wherein said opposite end of said screw element has a root diameter; and wherein said washer has a cylindrical outer surface with an outer diameter which is not greater than said root diameter of said opposite end of said screw element.
8. A bone anchor according to claim 1 wherein said screw element and said washer are made from a biocompatible material.
9. A bone anchor according to claim 8 , wherein said biocompatible material is a biocompatible polymer.
10. A bone anchor according to claim 9 , wherein said biocompatible polymer includes a therapeutic agent.
11. A bone anchor according to claim 1 wherein said cable member is attached to said washer at said opposite end thereof.
12. A bone anchor according to claim 11 wherein said cable member extends beyond said opposite end of said washer.
13. In combination, a bone anchor, comprising a screw element having a first passageway which extends axially through said screw element from one end thereof to an opposite end thereof and a washer having a second passageway which extends axially through said washer from one end thereof to an opposite end thereof, said one end of said washer being positionable adjacent to said opposite end of said screw element such that said first and second passageways are substantially aligned and such that said screw element is rotatable independently of said washer; a cable member attached to said washer and passing through said first and second passageways such that said cable member is not rotatable in response to the rotation of said screw element; and an insertion tool, comprising a rotatable shaft having a first opening at one end thereof, said first opening being sized and shaped so as to allow said cable member to pass therethrough, and engaging means, positioned on one end of said shaft, for engaging said bone anchor such that it can be rotated conjointly with said shaft in response to the rotation of said insertion tool.