Bone fixation system
An embodiment includes a bone fixation system comprising: a plate; and a tool; wherein: (a) the plate includes a hole to receive a bone anchor, (b) the hole includes a shelf, (c) the shelf includes a number of recesses; and (d) the hole is unthreaded and includes no resilient parts; wherein: (a) a distal end of the tool includes one or more lobes, (b) a number of lobes is no greater than the number of recesses, (c) each of the one or more lobes is configured to mate with one of the recesses. Other embodiments are described herein.
1. A bone fixation system comprising:
a plate; and
a tool;
wherein: (a) the plate includes an aperture configured to receive a bone anchor, (b) the aperture includes a long axis that traverses the aperture but does not intersect the plate, (c) the aperture includes a first opening and a second opening, (d) the aperture includes a plate projection and the plate projection projects inwardly from a wall of the aperture and towards the long axis, (e) the plate projection has a first surface and a second surface, and (f) the plate projection includes at least a first, second, and third plate reliefs along its perimeter;
wherein: (a) the tool includes a post having proximal and distal ends, (b) the distal end includes at least a first, second, and third tool projections, (c) a number of tool projections is not greater than a number of plate reliefs, (d) each tool projection is configured to mate with one of the plate reliefs; and (e) first and slope surfaces, wherein the first sloped surface directly connects to the first tool projection and the second sloped surface directly connects to the second tool projection;
wherein the first sloped surface forms a first ramp that thickens as the first slope surfaces advances away from the distal end of the tool and towards the proximal end of the tool;
wherein the third tool projection is proximal to the first tool projection; and
wherein the tool includes a void that is between a distal edge of the third tool projection and a proximal edge of the first tool projection;
the plate projection has a plate projection thickness between the first and second surfaces of the plate projection, the plate projection thickness measured parallel to the long axis of the aperture;
the void has a thickness measured parallel to a long axis of the tool and from the distal edge of the third tool projection to the proximal edge of the first tool projection; and the void thickness is less than the plate projection thickness.
2. The bone fixation system of claim 1 , wherein, based on the void thickness being less than the plate projection thickness, the void is configured to fixedly secure the plate projection via a resistance fit of the plate projection between the first and third tool projections.
3. The bone fixation system of claim 2 , wherein:
a distance extends parallel to the long axis of the tool and from the distal edge of the third tool projection to the distal end of the tool;
the distance is greater than the plate projection thickness.
4. The bone fixation system of claim 2 , wherein:
a first distance extends parallel to the long axis of the tool and from the distal edge of the third tool projection to a first location on the first sloped surface;
the first distance is equal to the plate projection thickness.
5. The bone fixation system of claim 4 , wherein:
a second distance extends parallel to the long axis of the tool and from the distal edge of the third tool projection to a second location on the first sloped surface;
the second distance is greater than the plate projection thickness.
6. The bone fixation system of claim 4 wherein the post includes a hollow conduit that extends from a proximal end of the tool to a distal end of the tool.
7. The bone fixation system of claim 6 , wherein the number of tool projections equals the number of plate reliefs.
8. The bone fixation system of claim 6 , wherein:
a first circular circumference is included in a plane that is orthogonal to the long axis of the tool;
the first circular circumference contacts an outermost tip of the first tool projection and an outermost tip of the second tool projection;
the first circular circumference has a first maximum diameter;
a second circular circumference is included in a plane that is orthogonal to the long axis of the aperture;
the second circular circumference contacts an outermost tip of the first plate relief projection and an outermost tip of the second plate relief;
the second circular circumference has a second maximum diameter;
the second maximum diameter is greater than the first maximum diameter.
9. The bone fixation system of claim 8 , wherein:
a third circular circumference is included in a plane that is orthogonal to the long axis of the aperture;
the third circular circumference contacts an innermost edge of the first plate relief and an innermost edge of the second plate relief;
the third circular circumference has a third maximum diameter;
the third maximum diameter is less than the first maximum diameter.
10. The bone fixation system of claim 2 wherein the first tool projection is proportioned to pass through the first plate relief when the tool is being fixed to the plate.
11. The bone fixation system of claim 2 wherein:
the plate includes no threads between the first and second openings;
the plate includes no resilient members between the first and second openings;
the first opening directly interfaces a first outer surface of the plate;
the second opening directly interfaces a second outer surface of the plate;
the first outer surface of the plate opposes the second outer surface of the plate.
12. The bone fixation system of claim 11 wherein:
the first opening has a first maximum diameter that is orthogonal to the long axis of the aperture;
the second opening has a second maximum diameter that is orthogonal to the long axis of the aperture;
the second maximum diameter is greater than the first maximum diameter.
13. The bone fixation system of claim 1 , wherein: (a) no portion of the aperture is threaded; (b) measured orthogonal to the long axis of the aperture, the second opening is wider than the first opening, and (c) measured parallel to the long axis of the aperture, the plate reliefs are further from the first opening than the second opening.
14. The bone fixation system of claim 13 wherein:
the aperture includes a counterbore;
the counterbore includes the first surface, the first surface being defined by a plane;
the plane is orthogonal to the long axis of the aperture;
the counterbore includes a sidewall, the sidewall extending parallel to the long axis of the aperture.
15. The bone fixation system of claim 13 comprising the bone anchor, wherein:
the bone anchor: (a) includes a head and a body, the head being coupled to the body, (b) has a long axis, (c) the body has an outer diameter that is orthogonal to the long axis and the head has an outer diameter that is orthogonal to the long axis, and (a)(iv) the outer diameter of the head is greater than the outer diameter of the body;
the bone anchor and the plate reliefs are collectively configured such that threads of the bone anchor head deform the first surface adjacent at least one of the plate reliefs when the bone anchor mates with the plate;
the bone anchor and the plate reliefs are collectively configured to lock the bone anchor to the plate in response to the threads of the bone anchor head deforming the first surface.