Osteosynthetic fixation plate

• US 4,683,878 A
• Filed: 04/29/1985
• Issued: 08/04/1987
• Est. Priority Date: 04/29/1985
• Status: Expired due to Fees

• Current Assignee: Biomet Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Kirschner Medical Corporation (Zimmer Biomet Holdings, Inc.)
• Inventors: Carter, Dennis R.
• Primary Examiner(s): Rosenbaum, C. Fred
• Assistant Examiner(s): SHEDD, CHARLES W
• Application Number:
  US06/728,185
• Time in Patent Office: 827 Days
• Field of Search: 128/92 D, 128/92 R, 128/92 YP, 128/92 YM, 128/92 YF
• US Class Current: 606/97
• CPC Class Codes: A61B 17/8014 the extension or compression force being caused by interaction of the plate hole and the screws

Abstract

The present invention comprises an elongated bone fixation plate with a center portion which bridges the fracture site. The central portion has a square cross-sectional shape. Two oppositely directed end portions extend axially from the central portion. The central portion has a width which is substantially less than the width of the end portions of the bone fixation plate. The end portions of the bone fixation plate have a plurality of elongated holes and each end portion tapers in thickness from adjacent the central portion to the outer terminating ends of the fixation plate. The plurality of holes are elongated in nature with each hole having a vertical distal wall and an inclined proximal end wall sloping toward the vertical distal wall. Each end portion has a uniform width and the entire bottom surface of each end portion may be concave in shape so as to provide a complementary mating surface with the fractured bone. By employing cortical or cancellous bone screws having a head whose bottom surface is rounded, the bone fixation plate draws each bone piece toward one another and places the bone pieces in compression at the fracture site when the plate and screws are fully secured to the bone.

Claims

1. An osteosynthetic bone fixation plate for securing fractured or disjointed bones, comprising:

a unitary, elongated, rigid plate having a central portion of sufficient length to bridge a fracture site, said central portion having a substantially square cross-sectional shape throughout its length, and two oppositely directed end portions, each of which extends axially from said central portion to a terminating end, said end portions having a width greater than said central portion and having a thickness which decreasingly tapers from said central portion to said terminating ends, said end portions also having a plurality of elongated holes, each of said holes having a vertical distal end wall and an inclined proximal end wall, whereby said plate, when secured to said fractured bones with a plurality of bone screws, places said fractured bones in compression with respect to one another at said fracture site.

2. The bone fixation plate of claim 1, further including a tapered portion extending between said central portion and each of said oppositely directed end portions so that said plate gradually increases in width from said square cross-sectional central portion to said oppositely directed end portions.

3. The bone fixation plate of claim 1, wherein said holes include a beveled edge so that said screws are countersunk when fully secured to said fractured bones.

4. The bone fixation plate of claim 1, wherein said inclined proximal end wall of said hole is concave.

5. The bone fixation plate of claim 1, wherein said inclined proximal end wall of said hole is convex.

6. The bone fixation plate of claim 1, made from an alloy having a titanium base with a 6%, by weight, aluminum, and 4%, by weight, vanadium.

7. The bone fixation plate of claim 1, wherein each of said holes is identically sized and in axial alignment with one another.

8. The bone fixation plate of claim 1, wherein said unitary, elongated, rigid plate has a bottom surface which is curved concavely so as to complementary mate with the surface of said fractured bones.

9. The bone fixation plate of claim 1, wherein said central portion and said two oppositely directed end portions have bottom surfaces, said bottom surface of said central portion is non-planar with said bottom surfaces of said two oppositely directed end portions, to prevent said plate from contacting said bones at said fracture site.

10. The bone fixation plate of claim 9, wherein said bottom surfaces of said two oppositely directed end portions have rounded edges adjacent said central portion to aid in increasing the vascular supply adjacent said fracture site.

11. An osteosynthetic bone fixation device for securing fractured bones, comprising a unitary, elongated, rigid plate and a plurality of cortical or cancellous bone screws, said unitary, elongated plate having a central portion of sufficient length to bridge a fracture site, said central portion having a substantially square cross-sectional shape throughout its length, and two oppositely directed end portions, each of which extends axially from said central portion to a terminating end, said end portions having a width greater than that of said central portion and having a thickness which decreasingly tapers from said central portion to said terminating ends, said end portions also having a plurality of elongated holes, each of said holes having a vertical distal end wall and an inclined proximal end wall, said bone screws having an elongated threaded portion and a head at one end thereof, said head having a bottom surface which is rounded so as to slidingly mate with said inclined proximal end wall, whereby said plate, when secured to said fractured bones with a plurality of said bone screws, places said fractured bones in compression with respect to one another at said fracture site.

12. The bone fixation plate of claim 11, further including a tapered portion extending between said central portion and each of said oppositely directed end portions so that said plate gradually increases in width from said square cross-sectional central portion to said oppositely directed end portions.

13. The bone fixation plate of claim 11, wherein said holes include a beveled edge so that said screws are countersunk when fully secured to said fractured bones.

14. The bone fixation plate of claim 11, wherein said inclined proximal end wall of said hole is concave.

15. The bone fixation plate of claim 11, wherein said inclined proximal end wall of said hole is convex.

16. The bone fixation plate of claim 11, made from an alloy having a titanium base with a 6%, by weight, aluminum, and 4%, by weight, vanadium.

17. The bone fixation plate of claim 11, wherein each of said holes is identically sized and in axial alignment with one another.

18. The bone fixation plate of claim 11, wherein said unitary, elongated, rigid plate has a bottom surface which is curved concavely so as to complementarily mate with the surface of said fractured bones.

19. The bone fixation plate of claim 11, wherein said central portion and said two oppositely directed end portions have bottom surfaces, said bottom surface of said central portion is non-planar with said bottom surfaces of said two oppositely end portions, to prevent said plate from contacting said bones at said fracture site.

20. The bone fixation plate of claim 19, wherein said bottom surfaces of said two oppositely directed end portions have rounded edges adjacent said central portion to aid in increasing the vascular supply adjacent said fracture site.