Method and instruments for inserting modular implant components
View Patent ↗An instrument is disclosed for inserting a modular implant, the instrument comprising a first end and a second end, the first end having engagement means for engaging a stem component of the modular implant, the engagement means comprising separation means for separating a body component of the modular implant and the stem component from one another so as to permit rotational positioning of the body component and the stem component relative to one another.
1. A multi-component modular joint prosthesis system comprising:
a body segment provided with a bore extending completely therethrough;
a neck segment comprising a projection that is slidably received in the body segment bore and is provided with a counterbore extending completely therethrough;
a stem segment constructed so that when in a first, extended position within the neck segment counterbore, said body segment and said neck segment are locked against rotation relative to one another, and when said stem segment is in a second, retracted position within the neck segment counterbore, said body segment and said neck segment are not locked against rotation relative to one another; and
an insertion tool for selective attachment to said stem segment, such that when said insertion tool is attached to said stem segment, said stem segment is free to assume a first, extended position or a second, retracted position, and when said insertion tool is attached to said stem segment and said stem segment is in the first, extended position within the body segment bore, such that said body segment and said neck segment are locked against rotation relative to one another, said insertion tool is movable to drive said stem segment from the first, extended position to the second, retracted position, whereby to permit said body segment and said neck segment to rotate relative to one another.
2. A multi-component modular joint prosthesis system according to claim 1 wherein said body segment further comprises a body portion and a neck portion.
3. A multi-component modular joint prosthesis system according to claim 1 wherein said stem segment is provided with tapered walls.
4. A multi-component modular joint prosthesis system according to claim 3 wherein said body segment bore is provided with a tapered portion, and said neck segment is provided with tapered walls adjacent to the body segment bore tapered portion.
5. A multi-component modular joint prosthesis system according to claim 1 wherein said insertion tool is provided with a threaded hole, and said stem segment is provided with a threaded end portion.
6. A multi-component modular joint prosthesis system according to claim 5 wherein the depth of the threaded hole is shorter than the length of said stem segment threaded end portion, such that when the threaded end portion is fully seated in the threaded hole, a gap remains between a proximal surface of said neck segment and a distal surface of said insertion tool.
7. A method for inserting a multi-component modular joint prosthesis comprising:
providing a body segment provided with a bore extending completely therethrough, a neck segment comprising a projection slidably received in the body segment bore and provided with a counterbore extending completely therethrough, a stem segment constructed so that when in a first, extended position within the neck segment counterbore, the body segment and the neck segment are locked against rotation relative to one another, and when in a second, retracted position within the neck segment counterbore, the body segment and the neck segment are not locked against rotation relative to one another, and an insertion tool for selective attachment to the stem segment, such that when the insertion tool is attached to the stem segment, the stem segment is free to assume either a first, extended position or a second, retracted position, and when the insertion tool is attached to the stem component and the stem component is in the first, extended position within the neck segment counterbore bore, such that the body segment and the neck segment are locked against rotation relative to one another, the insertion tool may be used to drive the stem segment from the first, extended position to the second, retracted position, whereby to permit the body segment and the neck segment to rotate relative to one another;
assembling the body segment and the neck segment and the insertion tool so that the insertion tool is attached to the stem segment, and the body segment and the neck segment are not locked against rotation relative to one another;
inserting the prosthesis into a bone;
arranging the body segment and the neck segment into desired positions; and
removing the insertion tool, whereby the body segment and the neck segment may be locked into the desired positions.
8. A method according to claim 7 wherein the body segment further comprises a body portion and a neck portion.
9. A method according to claim 7 wherein the stem segment is provided with tapered walls.
10. A method according to claim 9 wherein the body segment bore is provided with a tapered portion, and the neck segment is provided with tapered walls adjacent to the body segment bore tapered portion.
11. A method according to claim 7 wherein the insertion tool comprises a threaded hole, and the stem segment is provided with a threaded end portion.
12. A method according to claim 11 wherein the depth of the threaded hole is shorter than the length of the stem segment threaded end portion, such that when the threaded end portion is fully seated in the threaded hole, a gap remains between a proximal surface of the neck segment and a distal surface of the insertion tool.