Intramedullary nail
View Patent ↗The intramedullary nail has a longitudinal axis, a proximal end, a distal end, at least one hole that extends transversely to the longitudinal axis and is situated in a plane with a defined diameter to accommodate a locking element, as well as a longitudinal slot extending in the plane parallel to the longitudinal axis. In the unexpanded state of the intramedullary nail the longitudinal slot has a width b, measured perpendicularly to the plane in the region outside of the holes, said slot being maximum 0.6 times that of the smallest defined diameter of the holes.
1. An intramedullary nail comprising:
a nail body having a central longitudinal axis, a proximal end, and a distal end;
at least one hole extending through the nail body and having a central hole axis transverse to the longitudinal axis of the nail body, the at least one hole further having a diameter configured to accommodate a locking element, and the central hole axis located in a first plane;
a longitudinal slot extending through the nail body in the first plane, the longitudinal slot having an unexpanded width b measured perpendicularly to the first plane; and
an expansion limiting structure integral with the nail body for limiting expansion of the longitudinal slot, wherein the maximum unexpanded width b of the slot is 0.6 times the diameter of the at least one hole, wherein the expansion limiting structure is located at a distal end of the nail body, wherein the expansion limiting structure is different in shape than the at least one hole, and wherein: the expansion limiting structure includes a laterally extending channel open to a distal end of the longitudinal slot, the channel including first and second sides separated from one another by a predetermined distance selected so that, when portions of the nail body spaced from one another by the slot are separated by a desired maximum distance, further separation of the portions of the nail body is prevented by contact between the first and second sides of the channel.
2. The intramedullary nail of claim 1 , wherein the maximum unexpanded width b of the slot is 0.5 times the diameter of the at least one hole.
3. The intramedullary nail of claim 1 , wherein the nail includes at least two holes extending through the nail body and having central hole axes transverse to the longitudinal axis of the nail body, the at least two holes having two different diameters.
4. The intramedullary nail of claim 3 , further comprising at least two locking elements for introduction through the at least two holes, where a first locking element configured for introduction through a hole closer to the distal end of the nail has a diameter greater than the other locking element.
5. The intramedullary nail of claim 1 , wherein the longitudinal slot has a length L, where L is at least 10 times the diameter of the at least one hole.
6. The intramedullary nail of claim 5 , wherein the width b of the slot is generally uniform over the length L of the slot.
7. The intramedullary nail of claim 1 , wherein the nail is substantially hollow along its longitudinal axis.
8. The intramedullary nail of claim 1 , further comprising at least one locking element having a diameter.
9. The intramedullary nail of claim 8 , wherein the diameter of the locking element is greater than the diameter of the at least one hole.
10. The intramedullary nail of claim 9 , wherein the diameter of the locking element is at least 1.1 times that of the diameter of the at least one hole.
11. The intramedullary of claim 8 , wherein the intramedullary nail is elastically expanded in the region of the longitudinal slot when the locking element is introduced through the at least one hole.
12. The intramedullary nail of claim 11 , wherein the longitudinal slot has a length L, where L is chosen such that during insertion of the locking element through the at least one hole, the intramedullary nail only deforms elastically.
13. The intramedullary nail of claim 1 , further comprising an additional transverse hole extending through the nail substantially perpendicular to the first plane.
14. The intramedullary nail of claim 1 , wherein the expansion limiting structure is formed by at least one closed end of the nail.
15. An intramedullary nail comprising:
a nail body having a central longitudinal axis, a proximal end, and a distal end;
at least one hole extending through the nail body and having a central hole axis transverse to the longitudinal axis of the nail body, the at least one hole further having a diameter configured to accommodate a locking element, and the central hole axis located in a first plane;
a longitudinal slot extending through the nail body in the first plan, the longitudinal slot bending before reaching the distal end of the nail body and terminating laterally through the nail body to form a laterally extending channel including first and second sides separated from one another that permits expansion of the longitudinal slot up to a predetermined limit, separation of the portions of the nail body beyond the predetermined limit being prevented by contact between the first and second sides of the channel.
16. The intramedullary nail of claim 15 , wherein the longitudinal slot has a maximum unexpanded width b that is 0.6 times the diameter of the at least one hole, the width b measured perpendicularly to the first plane.
17. The intramedullary nail of claim 15 , wherein the nail includes at least two holes extending through the nail body and having central hole axes transverse to the longitudinal axis of the nail body, the at least two holes having two different diameters.
18. The intramedullary nail of claim 15 , further comprising an additional transverse hole extending through the nail substantially perpendicular to the first plane.