Point contact bone compression plate

• US 5,151,103 A
• Filed: 02/28/1991
• Issued: 09/29/1992
• Est. Priority Date: 11/03/1987
• Status: Expired due to Term

• Current Assignee: Synthes USA LLC (Johnson & Johnson)
• Original Assignee: Synthes USA LLC (Johnson & Johnson)
• Inventors: Straumann, Fritz, Tepic, Slobodan, Sutter, Franz, Perren, Stephen
• Primary Examiner(s): Isabella, David
• Assistant Examiner(s): BRITTINGHAM, DEBRA
• Application Number:
  US07/662,634
• Time in Patent Office: 579 Days
• Field of Search: 606/61, 606/69, 606/70, 606/72, 606/74
• US Class Current: 606/291
• CPC Class Codes: A61B 17/8028 Cushions, i.e. elements forming interface between bone plate and bone
• CPC Class Codes: A61B 17/8047 wherein the additional element surrounds the screw head in the plate hole A61B17/8052 takes precedence
• CPC Class Codes: A61B 17/8052 immobilised relative to screws by interlocking form of the heads and plate holes, e.g. conical or threaded
• CPC Class Codes: A61B 17/809 with bone-penetrating elements, e.g. blades or prongs bone staples A61B17/0642; intramedullary nails with a plate at an end A61B17/7233

Abstract

A bone plate for use in osteosynthesis having a plurality of contact elements extending from its lower surface so that contact between plate and bone is reduced to the minimum contact needed during attachment of the plate to a bone.

Claims

1. An implant for osteosynthesis comprising a biocompatible device for attachment to a bone, and a plurality of screws for attaching the device to the bone, the heads of said screws and the device having a predetermined friction angle relative to one another, said screws having conical heads and said device having complementary conical holes for receiving said heads in surface contact therewith, the cone angle of the conical holes being less than the friction angle between the holes and the screw head, thereby locking said screws to said device to prevent said device from sliding down the screw heads.

2. The implant claimed in claim 1, wherein the cone defining the hole has a cone taper of from about 1:

5 to about 1;

20.

3. The implant claimed in claim 1, wherein said device includes a plurality of clearance holes, each of said clearance holes having a compressible insert, each insert having one of said conical holes.

4. The implant claimed in claim 1, wherein the screws are self-tapping.

5. The implant claimed in claim 1, wherein the length of the screws are such that they will engage only one of the cortices of the bone to which the device is applied.

6. The implant claimed in claim 1, wherein the contact of the underside of said device with said bone is at a plurality of points.

7. The implant claimed in claim 1, wherein the device has a undersurface for application to the surface of a bone to be treated, the bone contact areas of said undersurface being less than 5% of the full undersurface area.

8. The implant claimed in claim 7, wherein the bone contact area is less than 2% of the full undersurface area.

9. Implant as claimed in claim 7, wherein the bone contact areas of the undersurface consist of contact studs made of a material which resorbable or dissoluble in body fluids.

10. The implant claimed in claim 1 and comprising clip-on springs mounted on said device and forming extensions on the undersurface of said device.

11. The implant claimed in claim 1, wherein said device is a plate.

12. The implant claimed in claim 1, wherein the heads of said screws have sockets and including elements for insertion into the sockets of said screw heads to expand said screw heads.

13. The implant claimed in claim 1, wherein the device includes a self compressing screw hole.

14. The implant claimed in claim 13, wherein the device includes a self-compressing screw hole.