Bone plate system with bone screws fixed by secondary compression

• US 20050187551A1
• Filed: 01/21/2005
• Published: 08/25/2005
• Est. Priority Date: 12/02/2002
• Status: Abandoned Application

• Current Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Inventors: Castaneda, Javier E., Orbay, Jorge L., Cavallazzi, Cesare, Graham, Robert
• Application Number:
  US11/040,779
• Publication Number:
  US 20050187551A1
• Time in Patent Office: Days
• US Class Current: 606/281
• 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 17/8047 wherein the additional element surrounds the screw head in the plate hole A61B17/8052 takes precedence

Abstract

A bone plating system includes a plate, fixed angle and variable angle bone screws, and corresponding set screws for each type of the bone screws. The plate includes common openings adapted to receive the variable and fixed angle bone screws, both of which can be locked relative to the plate with the set screws. In all modes of use, a set screw, sometimes in combination with a sliding washer, is then used to fix the level of compression and prevent loosening. In one mode of use, a bone screw can also be driven to cause displacement of the plate such that pressure is applied to maintain bone parts together about a fracture in tight engagement.

Claims

1. A bone plate system, comprising:

a) a bone plate including a bone screw hole;

b) a bone screw having a head portion residing within said bone screw hole, and a shaft extending below the plate; and

c) a set screw having a head and a shaft, wherein driving said set screw rotationally and axially into said set screw hole at least 180°

in rotation causes said set screw to directly a lateral compressive force to said head portion of said bone screw.

2. (canceled)

3. A bone plate system, comprising:

a) a bone plate including a bone screw hole having a lower cylindrical or frustoconical portion, and an upper cylindrical or frustoconical portion, and an adjacent threaded set screw hole;

b) a bone screw having a head portion residing within said bone screw hole, and a shaft extending below the plate; and

c) a set screw having a circular head and a shaft, wherein driving said set screw into said set screw hole causes said head of bone screw to become compressed between said plate at a side of said upper portion of said bone screw hole and said head of said set screw.

6. A bone plate system according to claim 3, wherein:

said bone screw hole includes a central spherically curved portion between said upper and lower portions.

7. A bone plate system according to claim 6, wherein:

said head portion of said bone screw has a spherically curved surface.

8. A bone plate system according to claim 6, wherein:

said head portion of said bone screw has a lower cylindrical or frustoconical portion and an upper cylindrical or frustoconical portion, such that when said head portion is seated in said bone screw hole said screw is fixed in a single axial orientation relative to said bone plate.

4-5. -5. (canceled)

9. A bone plate system, comprising:

a) a bone plate including a non-threaded bone screw hole with an axis;

b) a fixed angle bone screw having a head and a shaft with a substantially constant diameter, said head of said fixed angle screw shaped to seat in said bone screw hole only with its shaft concentric with said axis;

c) a variable angle bone screw having a head and shaft with said substantially constant diameter, said head of said variable angle screw shaped to stably seat in said bone screw hole with its shaft directed in any of several axes; and

d) means for locking said fixed angle bone screw relative to said plate.

10. A bone plate system according to claim 9, wherein:

said means for locking also can lock said variable angle bone screw relative to said plate, but does not lock said fixed angle and variable angle bone screws at the same time.

11. A bone plate system according to claim 9, wherein:

said means includes a set screw and a washer.

12-13. -13. (canceled)

14. A bone plate system, comprising:

a) a bone plate including a bone screw holes and a set screw holes, with each set screw hole being associated with only one bone screw hole;

b) a bone screw having a head portion residing entirely within one of said bone screw holes, and a shaft extending entirely below the plate; and

c) a plurality of set screws each having a head and a shaft, wherein driving one of said set screws into an associated screw hole causes a lateral compressive force to be applied to said head portion of said bone screw within one of said bone screw holes.

15. A bone plate system according to claim 14, wherein:

said set screw hole is threaded.

16. A bone plate system according to claim 14, wherein:

said set screw must be rotated at least 180°

to compress said head portion of said bone screw between said plate and said head of said set screw.

17. A bone plate system according to claim 14, wherein:

said set screw has a circumferential surface which has a spherically concave portion.

18. A bone plate system according to claim 14, wherein:

said set screw has a lower circumferential surface which is one of cylindrical and frustoconical, and an upper circumferential surface which forms an outer lip.

19. A bone plate system according to claim 18, wherein:

said outer lip is a conical section.

33. A bone plate system according to claim 14, wherein:

said bone screw hole and said set screw hole have parallel axes.

34. A bone plate system according to claim 33, wherein:

said axes are normal to a lower surface of said plate.

35. A bone plate system according to claim 14, wherein:

said plate includes an upper surface and a lower surface, and said bone screw hole and said set screw hole define a common opening at said upper surface and are separate at said lower surface.

20. A bone plate system, comprising:

a) a bone plate including a bone screw hole, an adjacent threaded set screw hole and a slot which extends from said bone screw hole and over said set screw hole;

b) a washer slidable within said slot and including an elongate opening and a contact face; and

c) a set screw having a circular head and a shaft, said shaft extending within said elongate opening and being threadably engaged in said set screw hole, wherein threadably inserting said set screw into said set screw hole causes a contact face of said washer to be laterally driven against said head portion of said bone screw to compress said head portion of said bone screw between said plate and said washer.

21. A bone plate system according to claim 20, wherein:

said slot includes a rear cam surface opposite said bone screw hole and when said set screw is driven into said plate said rear cam surface forces said washer toward said bone screw hole.

22. A bone plate system according to claim 21, wherein:

said set screw includes a cam surface which drives said washer against said bone screw.

23. A bone plate system according to claim 20, wherein:

said washer surrounds said shaft of said set screw.

24. A bone plate system according to claim 20, wherein:

said washer is provided only partially around said shaft of said set screw.

25. A bone plate system according to claim 20, wherein:

said contact face is provided with a textured surface.

26. A bone plate system according to claim 25, further comprising:

a bone screw having a head portion and a shaft, said head portion receivable within said bone screw hole and said shaft extendable below a lower surface of said plate, said head portion having a textured surface which when contacted by said contact face under force creates an interlock between the bone screw and washer.

27. A bone plate system according to claim 26, wherein:

said textured surfaces of said head portion of said bone screw and said contact face are different.

28. A bone plate system, comprising:

a) a bone plate including a bone screw hole and an adjacent straight slot;

b) an element longitudinally movable within said slot; and

c) means for longitudinally driving said element into said bone screw hole.

29. A method of implanting a bone plate against a long bone comprising:

a) positioning the bone plate against the long bone, the bone plate defining a bone screw hole;

b) providing a bone screw having a head and shaft;

c) inserting the bone screw through the bone screw hole such that the head of the bone screw provides a compressive force to said plate; and

d) driving a set screw to effect lateral compression of the head of the bone screw against the plate to lock the bone screw relative to the plate.

30. A method according to claim 29, wherein:

said bone screw is inserted at an oblique angle relative to said plate.

31. A method according to claim 29, wherein:

said driving includes rotating said set screw by at least 360°

.

32. A method according to claim 29, wherein:

said driving forces an element longitudinally against the head of the bone screw.