Bone plate
The present invention is directed to a bone plate and its method of use for reducing a bone fracture, the bone plate having a longitudinal axis, the bone plate comprising an upper surface, a lower surface, a first hole for engaging a head of a first bone anchor. The first hole is configured and adapted to fix a shaft of the first bone anchor along a first axis. A second hole is spaced apart from the first hole along the longitudinal axis. The second hole is for engaging a head of a second bone anchor, and is configured and adapted to fix a shaft of the second bone anchor along a second axis. The first hole and the second hole are configured such that the first axis and the second axis define a single plane and intersect at a point below the lower surface. The shafts of the first and second bone anchors may touch or nearly touch at the point of intersection, such that the first and second bone anchors form a truss.
1. A method for treating bone, comprising:
positioning a bone plate having a longitudinal axis on a target portion of a bone so that an upper surface of the bone plate faces away from the bone and a lower surface of the bone plate faces the bone;
inserting through a first hole of the bone plate a first bone anchor along a single, non-variable first axis defined by the first hole and locking a head of the first bone anchor within the first hole to lock a shaft of the first bone anchor along the first axis; and
inserting through a second hole of the bone plate a second bone anchor and locking a head of the second bone anchor within the second hole to lock a shaft of the second bone anchor along a single, non-variable second axis defined by the second hole, the first and second holes being configured such that the first and second axes define a single plane and intersect at a point within the bone and define an acute angle a at the point of intersection;
inserting the first and second bone anchors through the first and second holes, respectively, until the second bone anchor contacts the shaft of the first bone anchor proximate a point below the lower surface to form a truss.
2. The method of claim 1 , wherein the bone plate is positioned so that the first bone anchor is inserted into the bone on a first side of a fracture and the second bone anchor is inserted into the bone on a second side of the fracture and crosses the fracture so that a distal end of the second bone anchor is adjacent to the shaft of the first bone anchor.
3. The method of claim 1 , further comprising inserting a third bone anchor into the bone via a third hole of the bone plate anchor along a single, non-variable third axis defined by the third hole and locking a head of the third bone anchor within the third hole to lock a shaft of the third bone anchor along the third axis, the third axis intersecting the plane defined by the first and second axes at an angle.
4. The method of claim 3 , wherein the third hole is located along the longitudinal axis between the first and second holes.
5. The method of claim 1 , wherein the first hole is partially threaded and partially non-threaded.
6. The method of claim 5 , wherein the first hole has a non-threaded region adjacent to the upper surface, a threaded middle region, and a non-threaded region adjacent to the lower surface.
7. The method of claim 6 , wherein the upper region has, in a direction from the upper surface to the lower surface, a curved inward taper.
8. The method of claim 6 , wherein the middle region has, in a direction from the upper surface to the lower surface, a conical inward taper.
9. The method of claim 8 , wherein the middle region tapers at angle of 5° to 15°.
10. The method of claim 6 , wherein the lower region has, from the top surface to the lower surface, a conical outward taper.
11. The method of claim 6 , wherein the middle region has a diameter smaller than those of the upper and lower regions.
12. The method of claim 9 , wherein the lower region tapers outwardly at angle of 35° to 55°.
13. The method of claim 1 , wherein, after insertion, the tip of the second bone anchor is adjacent to the shaft of the first bone anchor.
14. The method of claim 1 , wherein, after insertion, the tip of the second bone anchor is adjacent to the tip of the first bone anchor.
15. The method of claim 1 , wherein the plane defined by the first and second axes lies at an angle relative to a plane bisecting the bone plate along the longitudinal axis.
16. The method of claim 15 , wherein the angle is between about 3° and about 6°.
17. The method of claim 1 , wherein the first and second axes form an acute angle of between 30° and about 45° at the point of intersection.
18. The method of claim 1 , wherein the first axis is substantially perpendicular to the lower surface of the bone plate.
19. The method of claim 1 , wherein the second axis forms an acute angle with the lower surface of the bone plate.
20. The method of claim 1 , further comprising inserting into a combination hole of the bone plate a fourth bone anchor, the combination hole having a first portion defining a substantially circular outer periphery defining a first center point and a second portion defining an elongated outer periphery that defines a second center point, wherein the elongated outer periphery is elongated in a direction substantially parallel to the longitudinal axis of the plate, and the second portion overlaps the first portion.