Screws for generating and applying compression within a body

Patent metadata

Field	Value
Publication number	US-9861413-B2
Application number	US-201414539650-A
Country	US
Kind code	B2
Filing date	Nov 12, 2014
Priority date	Nov 11, 2013
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A compression screw system, said compression screw system comprising:
a compression screw comprising a shaft, a screw thread formed on said shaft at a distal location, and a bone-engaging feature formed on said shaft at a proximal location, wherein at least a portion of said shaft disposed between said screw thread and said bone-engaging feature is capable of being stretched; and a holding element connectable to said compression screw for releasably holding said at least a portion of said shaft in a stretched condition.

First claim

What is claimed is:

1. A compression screw system comprising:
a compression screw comprising a shaft, a screw thread formed on said shaft at a distal location, and a bone-engaging feature formed on said shaft at a proximal location, at least a portion of said shaft disposed between said screw thread and said bone-engaging feature is capable of being stretched; and
a holding element connectable to said compression screw for releasably holding said at least a portion of said shaft in a stretched condition, wherein said holding element comprises a locking feature for releasably locking said holding element to said compression screw so as to hold said at least a portion of said shaft in said stretched condition.

2. The compression screw system according to claim 1 wherein said bone-engaging feature comprises a screw head.

3. The compression screw system according to claim 1 wherein said compression screw comprises a shape memory material.

4. The compression screw system according to claim 1 wherein said holding element is configured to engage a shoulder in said compression screw when said locking feature locks said holding element to said compression screw.

5. A method for treating a fracture, said method comprising:
longitudinally stretching a compression screw so that said compression screw is in a longitudinally stretched condition, wherein said compression screw is longitudinally stretched while said compression screw is maintained at a temperature below an austenite start temperature, wherein said compression screw comprises a shaft, a screw thread formed on said shaft at a distal location, and a bone-engaging feature formed on said shaft at a proximal location, at least a portion of said shaft disposed between said screw thread and said bone-engaging feature is capable of being stretched, a holding element connectable to said compression screw for releasably holding said at least a portion of said shaft in a stretched condition, and said compression screw comprises a shape memory material;
holding said compression screw in the longitudinally stretched condition by releasably connecting said holding element to said compression screw;
inserting said compression screw into bone while said compression screw is in the longitudinally stretched condition so that said compression screw extends across the fracture; and
releasing said compression screw from the longitudinally stretched condition by disconnecting said holding element from said compression screw so as to apply compression across the fracture.

6. The method according to claim 5 wherein said bone-engaging feature comprises a screw head.

7. The method according to claim 5 wherein said compression screw comprises an opening extending into said compression screw, and further wherein said holding element is extendable into said opening.

8. A method for treating a fracture, said method comprising:
longitudinally stretching a compression screw so that said compression screw is in a longitudinally stretched condition, wherein said compression screw comprises a shaft, a screw thread formed on said shaft at a distal location, and a bone-engaging feature formed on said shaft at a proximal location, at least a portion of said shaft disposed between said screw thread and said bone-engaging feature is capable of being stretched, a holding element is connectable to said compression screw for releasably holding said at least a portion of said shaft in a stretched condition, and said holding element comprises a locking feature for releasably locking said holding element to said compression screw;
holding said compression screw in the longitudinally stretched condition by releasably connecting said holding element to said compression screw;
inserting said compression screw into bone while said compression screw is in the longitudinally stretched condition so that said compression screw extends across the fracture; and
releasing said compression screw from the longitudinally stretched condition by disconnecting said holding element from said compression screw so as to apply compression across the fracture.

9. The method according to claim 8 wherein said holding element is configured to engage a shoulder in said compression screw when said locking feature locks said holding element to said compression screw.

10. A compression screw system, said compression screw system comprising:
a compression screw comprising a shaft capable of being stretched, said shaft having a proximal end, a distal end, and a lumen extending therebetween, said proximal end of said shaft comprising a proximal screw thread and said distal end of said shaft comprising a distal screw thread, said lumen comprising a distal bore, an intermediate counterbore communicating with said distal bore so as to define a first shoulder, and a proximal counterbore communicating with said intermediate counterbore so as to define a second shoulder, said proximal counterbore comprising a connection feature and said proximal end of said shaft comprising a drive feature for turning said compression screw; and
an internal retaining pin comprising a pin shaft having a proximal end, a distal end and a lumen extending therebetween, said proximal end of said pin shaft comprising a second connection feature configured to mate with said connection feature of said proximal counterbore of said compression screw, and said distal end of said pin shaft terminating in a distal end surface, said internal retaining pin comprising a pin drive feature for turning said internal retaining pin, and said internal retaining pin being sized such that, when said shaft of said compression screw is stretched, and when said internal retaining pin is inserted into said lumen of said compression screw such that said second connection feature of said internal retaining pin is engaged with said connection feature of said proximal counterbore of said compression screw and contacts said second shoulder of said compression screw, said distal end surface of said pin shaft engages said first shoulder of said compression screw, whereby to prevent foreshortening of the stretched compression screw.

11. The compression screw system according to claim 10 wherein said shaft comprises a shape memory material.

12. The compression screw system according to claim 11 wherein said shape memory material comprises Nitinol.

13. The compression screw system according to claim 10 wherein said connection feature of said compression screw comprises an internal screw thread and further wherein said second connection feature of said internal retaining pin comprises a proximal screw thread.

14. The compression screw system according to claim 10 wherein said proximal thread of said compression screw has more threads per inch than said distal thread of said compression screw.

15. The compression screw system according to claim 10 wherein said proximal thread of said compression screw and said distal thread of said compression screw mirror one another.

16. The compression screw system according to claim 10 wherein said drive feature of said compression screw comprises at least one selected from the group consisting of a slot, a cruciform recess, a hex recess, and a hexalobe recess.

17. The compression screw system according to claim 10 wherein said lumen of said internal retaining pin comprises a distal bore and a proximal counterbore communicating with said distal bore so as to define a pin shoulder.

18. The compression screw system according to claim 17 wherein said proximal counterbore of said internal retaining pin

Assignees

• Arthrex Inc

Inventors

• Palmer Matthew
• Devaney Robert
• El Khaja Ragheb
• Sennett Andrew
• Fonte Matthew

Classifications

• A61B17/8894

  holding the implant into or through which the screw is to be inserted (A61B17/7082, A61B17/7091 take precedence) · CPC title

• A61B17/8875

  Screwdrivers, spanners or wrenches · CPC title

• A61B17/8685

  comprising multiple separate parts · CPC title

• A61B17/864 Primary

  hollow, e.g. with socket or cannulated · CPC title

• A61B17/863

  with thread interrupted or changing its form along shank, other than constant taper · CPC title