Bone fixture assembly

Patent metadata

Field	Value
Publication number	US-9566098-B2
Application number	US-201213451118-A
Country	US
Kind code	B2
Filing date	Apr 19, 2012
Priority date	Apr 23, 2009
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

An assembly for rigid bone fixation includes a plate and a screw. The screw can be rotated freely within the plate in a non-locking configuration to secure the plate against the bone. A locking mechanism is engaged to prevent the screw from moving relative the plate. In one embodiment, the plate includes a threaded portion and a non-threaded portion. The screw head rotates within the non-threaded portion to tighten the screw and pull the plate against the bone. The locking mechanism can include a moveable nut that rotates within the threaded portion of the plate to lock the screw and plate in a locking mode. The assembly can be used for rigid fixation of bones that experience cyclic loads, such as the sternum and mandible. Methods of rigid bone fixation are also described.

First claim

What is claimed is:

1. A bone fixation device comprising:
a plate having a plurality of holes, at least one of the plurality of holes having a threaded interior;
a plurality of threaded screws to attach the plate to a bone, each screw having a threaded portion sized to engage the at least one hole having the threaded interior, a head with a displaceable head portion and a slot in the head; and
a screw locking displacer element that extends from a surface of the plate to engage the slot in the head to thereby displace a portion of the head relative to the screw to attach at least one of the plurality of threaded screws to the plate.

2. The device of claim 1 wherein the screw has a plurality of movable head portions.

3. The device of claim 1 wherein each hole comprises a first threaded section, a wider diameter nonthreaded section and a narrow diameter section.

4. The device of claim 1 wherein each threaded screw has a threaded length in a range of 0.4 to 1.4 cm.

5. The device of claim 1 wherein the plate has at least three holes, each hole having a helical ridge forming the threaded interior that engages a threaded screw with a plurality of rotations.

6. The device of claim 1 wherein each threaded screw has a thread spacing in a range of 0.8 to 1.6 mm.

7. The device of claim 1 wherein each threaded screw has cortical bone thread.

8. The device of claim 1 wherein the threads have a depth in a range of 1.5 to 2.5 mm.

9. The device of claim 1 wherein the plate comprises at least two holes on a first side to attach to a sternum bone on a first side of a patient's sternum and at least two holes on a second side of the plate to attach to a second side of the patient's sternum.

10. The device of claim 1 wherein the plate further comprises a plurality of barbs.

11. The device of claim 1 wherein the screw threading has a length to engage a first cortical layer and second cortical layer.

12. The device of claim 1 further comprising at least one of the threaded screws has threading to engage a cortical layer and cancellous bone layer.

13. A bone fixation device comprising:
a plate having a plurality of displacer elements, the plate further including a plurality of threaded holes; and
a plurality of threaded screws to attach the plate to a bone wherein each screw has a threaded portion sized to engage the threaded holes in the plate, at least one of the threaded screws having a head, a movable element attached to the head that engages one of the displacer elements on the plate to rigidly engage the plate wherein the movable element is displaced relative to the head upon engaging at least one of the displacer elements to attach the screw to the plate.

14. The device of claim 13 wherein each screw has a plurality of movable head elements.

15. The device of claim 13 wherein each hole comprises a first threaded section, a wider diameter nonthreaded section and a narrow diameter section to receive the head of one of the screws.

16. The device of claim 13 wherein each screw comprises a plurality of slots in the head.

17. The device of claim 13 wherein at least one of the displacer elements is positioned in a well in the plate.

18. The device of claim 13 wherein the head of the at least one threaded screw has an opening to receive the displacer element.

19. The device of claim 13 wherein the plate further comprises a plurality of barbs that engage bone on one side of the plate.

Assignees

• Dunn Raymond
• Billiar Kristen
• Lalikos Janice
• Christakis Alexander
• Dieselman John
• Univ Massachusetts
• Worcester Polytech Inst

Inventors

• Dunn Raymond
• Billiar Kristen
• Lalikos Janice
• Christakis Alexander
• Dieselman John

Classifications

• A61B17/8033

  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 title

• A61B17/8047

  wherein the additional element surrounds the screw head in the plate hole (A61B17/8052 takes precedence) · CPC title

• A61B17/8038

  the additional component being inserted in the screw head · CPC title

• A61B17/8076 Primary

  for the ribs or the sternum · CPC title

• A61B17/8042

  the additional component being a cover over the screw head · CPC title