Expandable bone nail
An intramedullary nail is suggested comprising a nail shaft with a lateral recess, with an expansion element being arranged in that recess, and an adjustment screw for adjusting the position and orientation of the expansion element relative to the nail shaft. A threaded bore may be formed in the nail shaft, wherein the threaded bore extends through the nail shaft and into the recess and is adapted to receive the adjustment screw.
1. An intramedullary nail, comprising:
a nail shaft having a central longitudinal axis, an outer surface extending in a longitudinal direction and in a circumferential direction, wherein a recess is formed in the outer surface of the nail shaft, the recess having a length measured in the longitudinal direction, a width measured in a circumferential direction and a depth measured from the outer surface in a direction to the central longitudinal axis, the nail shaft defining a channel extending through the nail shaft transverse to the central longitudinal axis;
an expansion element having a shape and size adapted to be accommodated in the recess, the expansion element including a pin positionable within the channel of the nail shaft; and
a first adjustment screw adapted to be accommodated in a first threaded bore extending through the nail shaft transverse to the central longitudinal axis, into the recess and partially into the expansion element, wherein the first adjustment screw is adapted to adjust a distance between the central longitudinal axis of the nail shaft and the expansion element.
2. The intramedullary nail of claim 1 , further comprising a second threaded bore extending through the nail shaft and into the recess, and a second adjustment screw.
3. The intramedullary nail of claim 1 , wherein the channel and the pin act in combination to guide an adjustment movement of the expansion element relative to the nail shaft.
4. The intramedullary nail of claim 1 , wherein the length of the recess is between 10 mm and 40 mm.
5. The intramedullary nail of claim 4 , wherein the length of the recess is between 20 mm and 25 mm.
6. The intramedullary nail of claim 1 , wherein the width of the recess is between 1 mm and 8 mm.
7. The intramedullary nail of claim 6 , wherein the width of the recess is between 2 mm and 5 mm.
8. The intramedullary nail of claim 1 , wherein the depth of the recess is 2 mm or less.
9. The intramedullary nail of claim 8 , wherein the depth of the recess is 1 mm or less.
10. The intramedullary nail of claim 1 , wherein the shape and size of the expansion element is determined such that a contour of the outer surface of the nail shaft at the recess is completed by the expansion element, when the expansion element is accommodated in the recess.
11. The intramedullary nail of claim 1 , wherein a cross section of the nail shaft at the recess is non-circular, perpendicular to the central longitudinal axis.
12. The intramedullary nail of claim 1 , wherein the nail shaft has a proximal section and wherein the recess is formed in the proximal section.
13. A method of using the intramedullary nail of claim 1 , comprising:
providing the nail shaft with the expansion element and the lateral recess,
arranging the expansion element in the recess of the nail shaft so that the expansion element does not protrude beyond the outer surface of the nail shaft,
inserting the nail shaft with the expansion element into the marrow channel of a bone,
adjusting the distance of the expansion element to the nail shaft by operating the first adjustment screw so that the expansion element moves out of the recess.