Easily implantable and stable nail-fastener for skeletal fixation and method

1. A nail-fastener apparatus for implantation into the medullary canal ( 26 ) surrounded by the cortex ( 28 ) of a bone ( 24 ) including a near cortex hole ( 40 ) having a near cortex hole diameter (D NC ) and a far cortex hole ( 42 ) having a far cortex hole diameter (D FC ) and with the near cortex hole diameter (D NC ) being greater than the far cortex hole diameter (D FC ) comprising;

an intramedullary nail ( 20 ) extending between a top end ( 30 ) and a bottom end ( 32 ) and defining a bore ( 34 ) extending transverse to said intramedullary nail ( 20 ) for insertion into the medullary canal ( 26 ) in the bone ( 24 ) surrounded by the cortex ( 28 ),

a threaded fastener ( 22 ) including a head ( 44 ) and an end ( 46 ) with a compression portion ( 48 ) and a threaded portion ( 50 ) extending along a fastener axis (A) therebetween,

said compression portion ( 48 ) having a compression portion diameter (D CP ) and said threaded portion ( 50 ) having a threaded portion diameter (D TP ) for extending through the near cortex hole ( 40 ) and the far cortex hole ( 42 ) both holes ( 40 , 42 ) radially overlapping said bore ( 34 ) with said threaded portion ( 50 ) threadedly engaging said bore ( 34 ),

a compression transmission device ( 54 ) having an exterior ( 56 ) and an interior ( 58 ) defining an interior space for transmitting the compressional load of said threaded fastener ( 22 ) to said intramedullary nail ( 20 ) during fixation and contacting the near cortex hole ( 40 ) for preventing movement of said compression transmission device ( 54 ) relative to the near cortex hole ( 40 ),

and characterized by,

said interior space being greater than said compression portion diameter (D CP ) of said fastener ( 22 ) for providing space at least partially about said threaded fastener ( 22 ) for allowing said fastener axis (A) to be variously disposed relative to said interior space.

2. An apparatus as set forth in claim 1 wherein said bore ( 34 ) is threaded and has a bore axis (B) extending between a near opening ( 36 ) and a far opening ( 38 ) transverse to said intramedullary nail ( 20 ) and having a bore diameter (D BR ).

3. An apparatus as set forth in claim 2 wherein said bore diameter (D BR ) includes a central bore diameter (D CBR ) disposed centrally between said near opening ( 36 ) and said far opening ( 38 ) of said bore ( 34 ).

4. An apparatus as set forth in claim 3 wherein said bore diameter (D BR ) increases from said central bore diameter (D CBR ) to said near opening ( 36 ) and from said central bore diameter (D CBR ) to said far opening ( 38 ) for allowing said fastener axis (A) to be skewed relative to said bore axis (B) while remaining threadedly engaged.

5. An apparatus as set forth in claim 1 wherein said compression portion diameter (D CP ) is smaller than said threaded portion diameter (D TP ).

6. An apparatus as set forth in claim 1 wherein said compression portion diameter (D CP ) is equal to said threaded portion diameter (D TP ).

7. An apparatus as set forth in claim 1 wherein said compression portion ( 48 ) is unthreaded between said head ( 44 ) and said threaded portion ( 50 ).

8. An apparatus as set forth in claim 1 wherein said compression portion ( 48 ) is threaded with threads continuing into said threaded portion ( 50 ).

9. An apparatus as set forth in claim 7 wherein said threaded fastener ( 22 ) includes an unthreaded portion adjacent to said end ( 46 ).

10. An apparatus as set forth in claim 3 wherein the far cortex hole diameter (D FC ) is equal to said central bore diameter (D CBR ).

11. An apparatus as set forth in claim 10 wherein said threaded portion diameter (D TP ) being equal to the far cortex hole diameter (D FC ) and said central bore diameter (D CBR ).

12. An apparatus as set forth in claim 1 further comprising said threaded fastener ( 22 ) extending through said compression transmission device ( 54 ) and said intramedullary nail ( 20 ) and the far cortex hole ( 42 ) so as to extend transversely to said intramedullary nail ( 20 ) for threadedly engaging said bore ( 34 ) and fixating said intramedullary nail ( 20 ) within the medullary canal ( 26 ).

13. An apparatus as set forth in claim 1 wherein said compression transmission device ( 54 ) is cylindrical and said exterior ( 56 ) of said compression transmission device ( 54 ) having an exterior diameter (D E ) and said interior ( 58 ) of said compression transmission device ( 54 ) having an interior diameter (D I ).

14. A method for implanting an intramedullary nail ( 20 ) into the medullary canal ( 26 ) surrounded by the cortex ( 28 ) of the bone ( 24 ) comprising the steps of;

creating a bore ( 34 ) in the intramedullary nail ( 20 ) extending transverse to the intramedullary nail ( 20 ) including threads,

forming a near cortex hole ( 40 ) in the cortex ( 28 ) and a far cortex hole ( 42 ) in the cortex ( 28 ) both in radially overlapping relationship to the bore ( 34 ),

providing a threaded fastener ( 22 ) including a head ( 44 ) and an end ( 46 ) with a compression portion ( 48 ) having a compression portion diameter (D CP ) and a threaded portion ( 50 ) having a threaded portion diameter (D TP ) extending along a fastener axis (A) therebetween,

providing a compression transmission device ( 54 ) having an exterior ( 56 ) and an interior ( 58 ) defining an interior space for transmitting the compressional load of the threaded fastener ( 22 ) to the intramedullary nail ( 20 ),

inserting a compression transmission device ( 54 ) into engagement with a near cortex hole ( 40 ) to prevent movement of the compression transmission device ( 54 ) relative to the near cortex hole ( 40 ),

extending the threaded fastener ( 22 ) through the compression transmission device ( 54 ) and the intramedullary nail ( 20 ) and through a far cortex hole ( 42 ) to extend transversely to the intramedullary nail ( 20 ) and threadedly engaging the bore ( 34 ) to fixate the intramedullary nail ( 20 ) within the medullary canal ( 26 ),

and characterized by,

providing the compression transmission device ( 54 ) with the interior space being greater than the compression portion diameter (D CP ) of the threaded fastener ( 22 ) for providing space at least partially about the threaded fastener ( 22 ) for allowing the fastener axis (A) to be variously disposed relative the interior space.

15. A method as set forth in claim 14 including creating the bore ( 34 ) having a bore axis (B) extending between a near opening ( 36 ) and a far opening ( 38 ) transverse to the intramedullary nail ( 20 ) and having a bore diameter (D BR ) including a central bore diameter (D CBR ) disposed centrally between the near opening ( 36 ) and the far opening ( 38 ) of the bore ( 34 ) in the intramedullary nail ( 20 ).

16. A method as set forth in claim 15 including creating the bore ( 34 ) wherein the bore diameter (D BR ) increases from the central bore diameter (D CBR ) to the near opening ( 36 ) and from the central bore diameter (D CBR ) to the far opening ( 38 ) for allowing the fastener axis (A) to be skewed relative to the bore axis (B) while remaining threadedly engaged.

17. A method as set forth in claim 14 including providing a threaded fastener ( 22 ) with the compression portion ( 48 ) having a compression portion diameter (D CP ) being smaller than the threaded portion diameter (D TP ).

18. A method as set forth in claim 14 including providing a threaded fastener ( 22 ) with the compression portion ( 48 ) having a compression portion diameter (D CP ) being equal to the threaded portion diameter (D TP ).

19. A method as set forth in claim 14 including providing the threaded fastener ( 22 ) with the compression portion ( 48 ) being unthreaded between the head ( 44 ) and the threaded portion ( 50 ).

20. A method as set forth in claim 14 including providing the threaded fastener ( 22 ) with the compression portion ( 48 ) being threaded with threads continuing into the threaded portion ( 50 ).

21. A method as set forth in claim 19 including providing the threaded fastener ( 22 ) with a second unthreaded portion ( 52 ) adjacent to the end ( 46 ).

22. A method as set forth in claim 16 including forming the near cortex hole ( 40 ) with a near cortex hole diameter (D NC ).

23. A method as set forth in claim 22 including forming the far cortex hole ( 42 ) having a far cortex hole diameter (D FC ) equal to the central bore diameter (D CBR ) and less than the near cortex hole diameter (D NC ).

24. A method as set forth in claim 23 including forming the near cortex hole ( 40 ) with the greater diameter before forming of the far cortex hole ( 42 ) with the lesser diameter.

25. A method as set forth in claim 23 including providing the threaded fastener ( 22 ) having the threaded portion diameter (D TP ) being equal to the far cortex hole diameter (D FC ) and the central bore diameter (D CBR ).

26. A method as set forth in claim 14 including inserting the compression transmission device ( 54 ) into engagement with the near cortex hole ( 40 ) to prevent movement of the compression transmission device ( 54 ) relative to the near cortex hole ( 40 ).

27. A method as set forth in claim 14 including providing the compression transmission device ( 54 ) being cylindrical and including an exterior ( 56 ) having an exterior diameter (D E ) and the interior ( 58 ) having an interior diameter (D I ).