Method and apparatus for bone fracture fixation

1. A method comprising:

determining a load to be supported across separated bone regions by a bridge region of a bone plate;

determining an acceptable cut force (CF) for the bridge region;

determining a cross-sectional area (a) of the bridge region based on the determined load;

determining a height (h) and a width (w) of the bridge region based on the following equation:

CF

=

(

(

S

⁢

⁢

1

)

⁢

(

a

)

+

C

⁢

⁢

1

)

⁢

(

w

h

max

)

S

⁢

⁢

2

wherein “S 1 ,” “C 1 ,” and “S 2 ” are constants for a given bridge material, constant “S 1 ” is a slope of a curve defined by a range of cut force versus cross-sectional area, constant “C 1 ” is a Y-intercept of the curve, and constant “S 2 ” is a slope of Ln (ARF) versus Ln (aspect ratio), wherein “ARF” is an aspect ratio factor that is defined by:

ARF

=

CF

⁢

⁢

1

(

CF

⁢

⁢

1

+

CF

⁢

⁢

2

)

/

2

wherein (h max ) is a maximum height of the bridge region, “CF 1 ” is a first cut force associated with one of the width (w) and the maximum height (h max ) of the bridge region, “CF 2 ” is a second cut force associated with the other of the width (w) and the maximum height (h max ), and the aspect ratio is a ratio between the maximum height (h max ) and the width (w); and

providing a bone plate including a bridge region having the height (h) and width (w) for securing the separated bone regions.

2. The method of claim 1 , wherein said determined acceptable cut force (CF) is a maximum allowable cut force for the bridge region.

3. The method of claim 1 , further comprising removing the bone plate from a sternum by severing the bridge region with a cutting tool.

4. The method of claim 3 , wherein the severing includes cutting along the width (w).

5. The method of claim 3 , further comprising securing the plate to the separated bone region, the plate including a first fixation region on a first end of the bridge region and a second fixation region on a second end of the bridge region, the securing including fixing the first fixation region to a first side of the separated bone region and fixing the second fixation region to a second side of the separated bone region.

6. The method of claim 5 , wherein the first fixation region includes a hook and the securing includes locating the hook around the first side of the separated bone region.

7. The method of claim 1 , further comprising securing the plate to a separated sternum, the plate including a first fixation region on a first end of the bridge region and a second fixation region on a second end of the bridge region, the securing including coupling the first fixation region to a first side of the separated sternum and coupling the second fixation region to a second side of the separated sternum.

8. The method of claim 7 , wherein the first fixation region includes a hook and the securing includes locating the hook around the first side of the separated sternum.

9. The method of claim 1 , wherein the cross-sectional area (a) is defined by the product of the maximum height (h max ) and the width (w).

10. The method of claim 1 , wherein the determined height (h) is less than or equal to the maximum height (h max ).

11. The method of claim 1 , wherein the first cut force (CF 1 ) is defined along the width (w).

12. The method of claim 1 , wherein the first cut force (CF 1 ) is defined along the height (h).

13. A bone plate comprising:

a first fixation region adapted to secure the bone plate to a first side of a separated bone region;

a second fixation region adapted to secure the bone plate to a second side of the separated bone region; and

a bridge region extending between and coupling said first and second fixation regions to one another, said bridge region defining a cross-sectional area (a) severable by a predetermined maximum allowable cut force (CF) and adapted to support a predetermined load across the separated bone region, said bridge region being defined by:

CF

=

(

(

S

⁢

⁢

1

)

⁢

(

a

)

+

C

⁢

⁢

1

)

⁢

(

w

h

max

)

S

⁢

⁢

2

and having a width (w) and a height (h) that is less than or equal to a maximum height (h max ), wherein “S 1 ,” “C 1 ,” and “S 2 ” are constants for a given bridge material, constant “S 1 ” is a slope of a curve defined by a range of cut force versus cross-sectional area, constant “C 1 ” is a Y-intercept of the curve, and constant “S 2 ” being a slope of Ln (ARF) versus Ln (aspect ratio), and “ARF” is an aspect ratio factor that is defined by:

ARF

=

CF

⁢

⁢

1

(

CF

⁢

⁢

1

+

CF

⁢

⁢

2

)

/

2

wherein “CF 1 ” is a first cut force associated with one of the width (w) and the maximum height (h max ) of said bridge region, “CF 2 ” is a second cut force associated with the other of the width (w) and the maximum height (h max ), and the aspect ratio is a ratio between the maximum height (h max ) and the width (w).

14. The bone plate of claim 13 , wherein said first fixation region includes a hook adapted to extend around the first side of a separated bone region.

15. The bone plate of claim 14 , wherein said second fixation region includes a first aperture adapted to receive a first fastener to couple the bone plate to the second side of the separated bone region.

16. The bone plate of claim 15 , wherein said first fixation region includes a second aperture located between said bridge region and said hook and adapted to receive a second fastener to couple the bone plate to the second side of the separated bone region.

17. The bone plate of claim 14 , wherein said hook is adapted to extend around a first side of a separated sternum.

18. The bone plate of claim 13 , wherein the cross-sectional area (a) is defined by the product of the maximum height (h max ) and the width (w).

19. The bone plate of claim 13 , wherein the first cut force (CF 1 ) is defined along the width (w).

20. The bone plate of claim 13 , wherein the first cut force (CF 1 ) is defined along the height (h).