Bone plate

• US 5,709,686 A
• Filed: 11/26/1996
• Issued: 01/20/1998
• Est. Priority Date: 03/27/1995
• Status: Expired due to Term

• Current Assignee: Synthes USA LLC (Johnson & Johnson)
• Original Assignee: Synthes USA LLC (Johnson & Johnson)
• Inventors: Schmoker, Roland, Talos, Gilbert
• Primary Examiner(s): Jackson, Gary
• Assistant Examiner(s): Reip, David O.
• Application Number:
  US08/750,114
• Time in Patent Office: 420 Days
• Field of Search: 606/69, 606/70, 606/71, 606/72, 606/73
• US Class Current: 606/281
• CPC Class Codes: A61B 17/8014 the extension or compression force being caused by interaction of the plate hole and the screws
• CPC Class Codes: A61B 17/8057 the interlocking form comprising a thread

Abstract

The invention concerns a bone plate comprising holes (2) running in the longitudinal plate direction and receiving bone screws. The major axis D_L as seen in the direction of the longitudinal plate axis (1) of at least one hole (2) is larger than the minor axis D_Q of this hole (2) running perpendicularly to the plate longitudinal axis (1). At least one of these holes (2) evincing a minor axis D_Q perpendicular to the plate axis (1) comprises a partial thread (3) in the area of this minor axis D_Q to receive a bone screw with a thread head.

Claims

1. A bone plate comprising:

an elongated plate defining a longitudinal axis along its length having an upper surface, a lower surface for application to a bone, and a plurality of elongated holes arranged along the length of the plate for receiving bone screws, said elongated holes being oblong in shape and having a major axis D_L and a minor axis D_Q, with D_L being greater than D_Q,

wherein at least one of said elongated holes includes partial threaded portions arranged on an inner wall of the elongated hole, and is configured for seating a bone screw having a threaded head.

2. The bone plate of claim 1, wherein each elongated hole has a lower part which extends to the lower surface of the plate, and an upper part which extends to the upper surface of the plate, and the partial threaded portion is positioned in the lower part of the elongated hole.

3. The bone plate of claim 2, wherein the lower part of said at least one elongated hole includes a flared surface which extends outwardly to the lower surface of the bone plate.

4. The bone plate of claim 3, wherein the partial threaded portions extend around opposing portions of the inner wall in an area of the minor axis, and the lower flared surface extends outwardly adjacent to the partial threaded portions.

5. The bone plate of claim 3, wherein said lower flared surface is conically shaped.

6. The bone plate of claim 2, wherein said at least one elongated hole further comprises an outwardly flared countersink surface adjacent the upper surface for slidingly receiving a bone screw having a spherical head.

7. The bone plate of claim 6, wherein the outwardly flared countersink surface is shaped and configured for mating engagement with the bone screw.

8. The bone plate of claim 6, wherein the outwardly flared countersink surface has an angle relative to the longitudinal axis of the plate which is sufficient to produce a ramping effect for engagement with a bone screw.

9. The bone plate of claim 8, wherein the outwardly flared countersink surface has an angle of 57°

.

10. A method for compressing a bone using the bone plate of claim 6, comprising:

positioning said bone plate on a surface;

inserting a bone screw having a spherical head into at least one elongated hole at one end of said hole; and

screwing said bone screw into the surface so that as the spherical head of the screw contacts the outwardly flared countersink surface of the hole, the spherical head of the screw ramps downwardly along the flared surface to move the plate to generate compression.

11. The bone plate of claim 1, wherein D_L /D_Q is within the range of 1.01 to 3.

12. The bone plate of claim 1, wherein D_L /D_Q is within the range of 1.1 to 1.5.

13. The bone plate of claim 1, wherein the major axis of at least one of said elongated holes is positioned along the longitudinal axis of the plate.

14. The bone plate of claim 1, wherein the lower surface has a curved shape for contacting a bone.