Bone fracture fixation systems with both multidirectional and unidirectional stabilization pegs

1. A peg for use in a threaded peg hole in a fracture fixation device, comprising:

a head and a non-threaded shaft, said head including a proximal portion having an external thread, a distal portion having a substantially spherically convex surface, and means for receiving a rotational driver.

2. A peg system for use in a fracture fixation device, comprising:

a) a peg having a non-threaded head and a non-threaded shaft, said head defining a proximal cup provided with means for receiving a rotational driver and a distal portion having a substantially spherically convex surface; and

b) a cap having an external thread, means for receiving a rotational driver, and a protuberance adapted to engage within said proximal cup of said peg.

3. A kit for a fracture fixation system, comprising:

a) a fracture fixation device defining at least first and second like peg holes, each said peg hole having an upper portion provided with an internal thread;

b) a first peg couplable within at least said first peg hole, said first peg having a head and a shaft, said head having an external thread engageable with said internal thread, means for receiving a rotational driver;

c) a second peg couplable within at least said second peg hole, said second peg having a head and a shaft; and

d) a cap having an external thread that is engageable with said internal thread of said second peg hole and means for receiving a rotational driver.

4. A kit according to claim 3 , wherein:

said cap includes an element for engagement with said head of said second peg to angularly fix said head of said second peg within said second peg hole.

5. A kit according to claim 4 , wherein:

said element is adapted to clamp against said head of said second peg to provide said angular fixation.

6. A kit according to claim 4 , wherein:

said head of said second peg includes a cup having a surface area, and said element of said cap includes a protuberance adapted to define a substantially small contact area relative to said surface area of said cup.

7. A kit according to claim 4 , wherein:

said cap comprises a base and a set screw,

said base includes said external thread adapted to thread with said internal thread of said first and second peg holes an internal thread, and said means for receiving a rotational driver, and

said set screw includes an external thread adapted to thread with said internal thread of said base, a second means for receiving a rotational driver, and said element.

8. A kit according to claim 7 , wherein:

said external thread of said base has a first pitch, said external thread of said set screw has a second pitch, and said first pitch is greater than said second pitch.

9. A kit according to claim 3 , wherein:

said head of said second peg defines a cup having means for receiving a rotational driver.

10. A kit according to claim 4 , wherein:

said head of said second peg defines a concave surface, and said element has a spherically-curved convex surface corresponding to said concave surface.

11. A kit according to claim 3 , wherein:

said first peg hole includes a lower portion having a substantially spherically concave surface, said first peg includes a portion having a substantially spherically convex surface corresponding to said spherically concave surface, said substantially spherically concave surface and said substantially spherically convex portion intended for contact with each other.

12. A kit according to claim 3 , wherein:

said shaft of said first peg is non-threaded.

13. A kit according to claim 3 , wherein:

said shaft of said second peg is non-threaded.

14. A kit according to claim 13 , wherein:

said second peg includes means for receiving a rotational driver.

15. A kit according to claim 3 , wherein:

said fixation device is a plate.

16. A kit according to claim 3 , wherein:

said fixation device is nail-plate.

17. A kit according to claim 3 , wherein:

when said first and second pegs are fixed within said at least first and second peg holes, said first and second pegs are collectively oriented to provide a framework for supporting fractured bone fragments, said first and second pegs of said framework defining a plurality of non-parallel axes.

18. A kit according to claim 3 , wherein:

said at least first and second peg holes includes at least three peg holes closely spaced in a linear or curvilinear arrangement.

19. A kit according to claim 3 , wherein:

said fixation device includes a plate portion defining said at least first and second peg holes.

20. A kit according to claim 19 , wherein:

said plate portion has a body portion and a head portion angled relative said body portion, said head portion defining said at least first and second peg holes.

21. A kit according to claim 19 , wherein:

said fixation device also includes a nail portion extending from said plate portion.

22. A kit according to claim 3 , where

said fixation device includes at least one non-threaded screw hole.

23. A fracture fixation system, comprising:

a) a fracture fixation device defining at least one peg hole, said peg hole having an upper portion provided with an internal thread, and a lower portion having a substantially spherically concave surface;

b) a first peg having a head and a shaft, said head including a first portion having an external thread adapted to thread with said internal thread, a second portion having a substantially spherically convex surface corresponding to said substantially spherically concave surface, and means for receiving a rotational driver;

c) a second peg having a head and a shaft, said head including a first portion defining a cup and having a substantially spherically convex surface corresponding to said substantially spherically concave surface; and

d) a cap having an external thread adapted to thread with said internal thread, means for receiving a rotational driver, and an element sized to be received within said cup of said second peg.

24. A fracture fixation system according to claim 23 , wherein:

at least one of said substantially spherically concave surface of said device, said substantially spherically convex surface of said first peg and said substantially spherically convex surface of said second peg is provided with a relatively high coefficient of friction.

25. A fracture fixation system according to claim 23 , wherein:

one of said shaft of said first peg and said shaft of said second peg is non-threaded.

26. A fracture fixation system according to claim 23 , wherein:

said fixation device is a plate device.

27. A fracture fixation system according to claim 26 , wherein:

said plate device is a volar plate.

28. A fracture fixation system according to claim 23 , wherein:

said fixation device is a nail-plate device.

29. A fracture fixation system according to claim 23 , wherein:

said fixation device includes a plurality of peg holes.

30. A fracture fixation system according to claim 23 , wherein:

said cup of said second peg includes a surface area, and said element of said cap includes a protuberance adapted to define a substantially small contact area relative to said surface area of said cup.

31. A fracture fixation system according to claim 23 , wherein:

said a cap comprises a base and a set screw,

said base includes said external thread adapted to thread with said internal thread of said at least one peg hole, an internal thread, and said means for receiving a rotational driver, and

said set screw includes an external thread adapted to thread with said internal thread of said base, a second means for receiving a rotational driver, and said element.

32. A fracture fixation system according to claim 31 , wherein:

said external thread of said base has a first pitch, said external thread of said set screw has a second pitch, and said first pitch is greater than said second pitch.

33. A fracture fixation system according to claim 23 , wherein:

said cup of said second peg defines means for receiving a rotational driver.

34. A fracture fixation system according to claim 23 , wherein:

said at least one peg hole includes first and second peg holes, said first peg hole defines a first axis and said second peg hole defines a second axis,

wherein said first peg is coupled within said first peg hole in alignment with said first axis, and said second peg is coupled within said second peg hole at an angle relative to said second axis.

35. A fracture fixation system according to claim 34 , wherein:

said first and second axes are parallel.

36. A fracture fixation system according to claim 34 , wherein:

said angle is within a range of ±15° relative to said second axis.

37. A method of treating a bone fracture, comprising:

a) providing a fixation device having a plurality of like threaded peg holes, each of said peg holes defining an axis, having an upper portion provided with an internal thread, and a lower portion having a substantially spherically concave surface;

b) positioning the fixation device over the bone fracture;

c) drilling holes through the peg holes into the bone, wherein a first of the drilled holes is drilled substantially coaxial with the axis through a peg hole, and a second of the drilled holes is drilled at an angle relative to the axis through a peg hole;

d) providing a first peg having a head and a shaft, said head including an external thread adapted to thread with said internal thread, a portion having a substantially spherically convex surface corresponding to said substantially spherically concave surface, and means for receiving a rotational driver;

e) inserting said first peg through one of the peg holes such that the shaft of the first peg extends into the first drilled hole;

f) providing a second peg and a discrete cap, said second peg having a head and a shaft, said head of said second peg including a portion defining a cup and having a substantially spherically convex surface corresponding to said substantially spherically concave surface, and said cap having an external thread, means for receiving a rotational driver, and an element sized to be received within said cup of said second peg;

g) inserting the second peg through another of the peg holes such that the shaft of the second peg extends through the second drilled hole; and

h) threadably engaging the cap in the other of the peg holes until a portion of the cap engages the head of the second peg.

38. A method according to claim 37 , wherein:

said threadably engaging the cap causes clamping of the head of the second peg between the cap and the fixation device.

39. A method according to claim 37 , wherein:

said providing said second peg and a discrete cap includes providing said second peg with a non-threaded shaft.