Volar fixation system with articulating stabilization pegs

• US 20010011172A1
• Filed: 12/12/2000
• Published: 08/02/2001
• Est. Priority Date: 02/01/2000
• Status: Active Grant

• Current Assignee: Biomet Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Hand Innovations LLC (Johnson & Johnson)
• Inventors: Orbay, Jorge L., Leone, James
• Granted Patent: US 6,440,135 B2
• Time in Patent Office: Days
• US Class Current: 606/69
• CPC Class Codes: A61B 17/1728 for holes for bone plates or plate screws
• CPC Class Codes: A61B 17/1782 for the hand or wrist
• CPC Class Codes: A61B 17/68 Internal fixation devices , including fasteners and spinal fixators, even if a part thereof projects from the skin bone staples A61B17/0642
• CPC Class Codes: A61B 17/7208 Flexible pins, e.g. ENDER pins
• CPC Class Codes: A61B 17/80 Cortical plates , i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates
• CPC Class Codes: A61B 17/8033 having indirect contact with screw heads, or having contact with screw heads maintained with the aid of additional components, e.g. nuts, wedges or head covers
• CPC Class Codes: A61B 17/8042 the additional component being a cover over the screw head
• 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 17/8061 specially adapted for particular bones A61B17/70 and A61B17/74 take precedence
• CPC Class Codes: A61B 17/84 Fasteners therefor or fasteners being internal fixation devices
• CPC Class Codes: A61B 17/863 with thread interrupted or changing its form along shank, other than constant taper

Abstract

A volar fixation system includes a T-shaped plate intended to be positioned against the volar side of the radial bone, a plurality of bone screws for securing the plate along an non-fractured portion of the radial bone, and a plurality of bone pegs which extend from the plate and into bone fragments of a Colles'"'"' fracture. The plate is a T-shaped plate including a plurality of screw holes and a plurality of threaded peg holes. According to a preferred aspect of the invention, pegs can be articulated through a range of angles within respective peg holes and fixed at a desired angle within the range. The volar plate is positioned against the radius and screws are inserted through the screw holes to secure the volar plate to the radius. The bone fragments are aligned, and the holes are drilled through the peg holes into the fragments. The pegs are inserted through the peg holes and into the drilled holes in the bone. The pegs can be oriented at various angles relative to an axis normal to the lower surface of the plate. For each peg, once the peg has been appropriately positioned within the peg hole, a set screw is thread into the peg hole and tightened, thereby securing the peg in the selected orientation.

Claims

1. A volar fixation system, comprising:

(a) a substantially rigid plate including a distal head portion and a proximal body portion angled relative to said head portion,

said head portion defining a plurality of peg holes adapted to individually receive fixation pegs therethrough, said peg holes having an upper portion and a lower portion, said upper portion having a first thread, and said lower portion having spherical radius of curvature,

said body portion including at least one screw hole;

(b) a plurality of pegs each having a head portion and a shaft portion, said shaft portion sized to be received in said peg holes, and said head portion having an outer surface with substantially a same spherical radius of curvature as said lower portion of said peg holes; and

(c) a plurality of set screws each having a body including a second thread rotationally engageable with said first thread, and a proximal rotational engagement means for engaging said set screw and applying a rotational force thereto,

wherein when said pegs are provided into respective peg holes, each said peg may be positioned at any angle within a predefined range of angles relative to an axis normal to a lower surface of said head portion of said volar plate, and once so positioned, respective set screws when thread into said upper portions of said peg holes fix said pegs in their respective angles.

2. A volar fixation system according to

claim 1

, wherein:

said predefined range includes 200 relative to said axis normal to said lower surface of said head portion of said volar plate.

3. A volar fixation system according to

claim 1

, wherein:

said lower portion of each of said peg holes is processed to have a relatively high coefficient of friction.

4. A volar fixation system according to

claim 1

, wherein:

said outer surface of said head portion of each of said pegs is processed to have a relatively high coefficient of friction.

5. A volar fixation system according to

claim 1

, wherein:

said peg holes are linearly arranged.

6. A volar fixation system according to

claim 1

, wherein:

said head portion defines a medial side and a lateral side, and said peg holes are arranged in a generally medial to lateral direction wherein successive lateral peg holes are situated distally relative to adjacent peg holes.

7. A volar fixation system according to

claim 1

, wherein:

said peg holes lie along a curve.

8. A volar fixation system according to

claim 1

, wherein:

said head portion includes exactly four peg holes.

9. A volar fixation system according to

claim 1

, wherein:

a taper is provided at an intersection of said head and shaft of each of said pegs.

10. A volar fixation system according to

claim 9

, wherein:

a bevel is provided about a lower opening of each of said peg holes.

11. A volar fixation system according to

claim 1

, wherein:

each of said head portions of said pegs is concave, and each of said set screws includes a distal convex portion seating with said head portions.

12. A volar fixation system according to

claim 11

, wherein:

said concave and convex portions are each defined by a substantially same radius.

13. A volar fixation system according to

claim 1

, wherein:

said outer surface of said head portion defines less than a hemisphere.

14. A volar fixation system according to

claim 1

, wherein:

said rotational engagement means of each of said set screws is a hex socket.

15. A volar fixation system according to

claim 1

, wherein:

said shaft portion of each of said pegs is a non-threaded cylinder.

16. A volar fixation plate, comprising:

a substantially rigid plate including a distal head portion and a proximal body portion angled relative to said head portion,

said head portion defining a plurality of peg holes adapted to individually receive fixation pegs therethrough, said peg holes having an upper portion and a lower portion, the lower portion having spherical radius of curvature,

said body portion including at least one screw hole.

17. A volar fixation plate according to

claim 16

, wherein:

said upper portion includes a thread.

18. A volar fixation plate according to

claim 16

, wherein:

said lower portion is processed to have a relatively high coefficient of friction.

19. A volar fixation plate according to

claim 16

, wherein:

said peg holes are linearly arranged.

20. A volar fixation plate according to

claim 16

, wherein:

said head portion defines a medial side and a lateral side, and said peg holes are arranged in a generally medial to lateral direction wherein successive lateral peg holes are situated distally relative to adjacent peg holes.

21. A volar fixation plate according to

claim 16

, wherein:

said peg holes lie along a curve.

22. A volar fixation plate according to

claim 16

, wherein:

said head portion includes exactly four peg holes.

23. A peg for insertion into a peg hole in a fracture fixation system, comprising:

(a) a head having an outer surface with a first substantially spherical radius of curvature and a concavity with a second substantially spherical radius of curvature, said head defining less than a hemisphere; and

(b) a cylindrical shaft coupled to said head, said shaft including a taper adjacent said head.

24. A peg according to

claim 23

, wherein:

said outer surface of said head portion is processed to have a relatively high coefficient of friction.

25. A set screw for set a peg in a peg hole, comprising:

a body including a thread, a proximal rotational engagement means for engaging said set screw and applying a rotation force thereto, and a distal hemispherical portion.

26. A set screw according to

claim 25

, wherein:

said distal hemispherical portion defines a radius smaller than a radius of said body.

27. A set screw according to

claim 25

, wherein:

said rotational engagement means is a hex socket.