Force distribution implant, assembly and kit
An implant for use with a bone screw for fixation of at least one bone or bone fragments. The implant includes a top end and a bottom end. The implant may also include an exterior surface extending from the top end to the bottom end and a central bore extending from the top end to the bottom end along a central axis. The implant may further include a slot extending through the exterior surface and intersecting with the central bore of the implant. A bone fixation assembly including a fixator and an implant configured to engage the fixator is also disclosed. A surgical kit for bone fixation is also disclosed. The surgical kit includes at least one force distribution member and at least one elongate member.
1. An implant for use with a bone fastener with a head portion and a shaft portion extending from the head portion along an axis of the bone fastener, comprising:
an annular body portion extending from a top end to a bottom end, comprising:
an exterior surface; and
an annular interior surface extending from the top end to the bottom end defining a central bore extending from the top end to the bottom end along a central axis;
a rim portion extending radially outwardly from the body portion at the top end; and
a slot extending entirely through a section of the rim portion and the body portion such that the slot is in communication with the central bore,
wherein the exterior surface extends from the bottom end to the rim portion, the exterior surface being convex in a direction extending along the central axis between the bottom end and the rim portion,
wherein the interior surface of the body portion comprises a first interior surface portion extending from the top end toward the bottom end that is planar in a direction transverse to the central axis, and a second interior surface portion extending from the bottom end to the first interior surface portion that is concave in a direction extending along the central axis,
wherein the slot extends along a slot axis that is angled with respect to the central axis, and
wherein a width of the slot extending perpendicular to the slot axis is equal to or greater than a width of the shaft portion of the bone fastener extending perpendicular to the axis of the bone fastener.
2. The implant of claim 1 , wherein the inner surface of the body portion includes a first inner diameter at the top end and a second inner diameter at the bottom end, the first inner diameter being larger than the second inner diameter.
3. The implant of claim 1 , wherein the interior surface is configured to engage a head of a bone fastener.
4. The implant of claim 1 , wherein the exterior surface is tapered from the top end to the bottom end.
5. The implant of claim 1 , wherein the rim portion is configured to engage a bone surface.
6. The implant of claim 1 , wherein the central bore is configured to engage a top portion of a bone fastener.
7. The implant of claim 6 , wherein the shaft portion of the bone fastener comprises a smooth end and a threaded end, wherein the smooth end of the shaft portion is integral with the head portion.
8. The implant of claim 7 , wherein the slot and the central bore are configured to receive the smooth end of the shaft portion therethrough.
9. The implant of claim 7 , wherein an inferior end of the head portion bears against the interior surface of the body portion.
10. The implant of claim 1 , wherein the slot axis is angled between 20 to 30 degrees relative to the central axis.
11. The implant of claim 10 , wherein the slot is offset from the central axis between 0.3 mm and 1.6 mm.
12. The implant of claim 1 , wherein the head portion of the bone fastener slidingly engages the concave first interior surface portion of the interior surface.
13. The implant of claim 1 , wherein the exterior surface of the body portion is arcuately convex in a direction extending along the central axis between the bottom end and the rim portion.
14. The implant of claim 1 , wherein the second interior surface portion of the body portion is arcuately concave in a direction extending along the central axis.
15. The implant of claim 1 , wherein the top end of the body portion defines a top boundary of the implant.
16. The implant of claim 1 , wherein a top surface of the rim portion extends downwardly toward the bottom end of the body portion as it extends radially outwardly from the top end of the body portion.
17. The implant of claim 1 , wherein opposing sides defining the slot extend partially about the central axis as the opposing sides extend from the top end to the bottom end along the slot axis.
18. The implant of claim 1 , wherein opposing sides defining the slot are planar and parallel to each other, as the opposing sides extend from the top end to the bottom end.