Intramedullary fixation device for metaphyseal long bone fractures
View Patent ↗A fixation system ( 10 ) includes a device having a nail portion ( 12 ) and a plate portion ( 14 ), preferably horizontally and vertically offset relative to the nail portion by a neck portion ( 16 ). The nail portion ( 12 ) includes preferably threaded screw holes ( 24, 26 ), and the plate portion ( 14 ) includes longitudinally displaced peg holes ( 50, 52, 54 ), each of which is adapted to orient a peg ( 56, 58, 60 ) in a different orientation from the others. The system ( 10 ) also includes unicortical screws ( 28 ) having a reasonably large head ( 36 ) adapted to seat against the outer surface of the bone and a threaded shaft ( 32 ) adapted to engage in the screw holes ( 24, 26 ), and pegs ( 56, 58, 60 ) adapted to engage in the peg holes ( 50, 52, 54 ). Where threaded screw holes ( 24, 26 ) are used, bone is clamped between the nail portion ( 12 ) and the head ( 36 ) of the unicortical screws ( 28, 30 ). The pegs ( 56, 58, 60 ) provide stabilization and support for subchondral fragments. Moreover, as the pegs ( 56, 58, 60 ) preferably enter the subchondral fragments from a plurality of directions, additional fixation of the device ( 10 ) into the bone is provided.
1. A one-piece bone fracture fixation device for use with a fastener having a head portion with a diameter larger than a shaft portion, said device for stabilization of a fracture of a bone of an upper extremity, the bone having a metaphysis and diaphysis, the diaphysis defining a medullary canal, said device comprising:
a) an elongate nail portion having a first length and including a first portion with a first diameter with at least one threaded screw hole extending therein and an opposite second portion having a smaller diameter than said first portion and having a decreased rigidity relative to said first portion thereby permitting the second portion to flex relative to the first portion, an entirety of said nail portion sized to be received within the medullary canal of the bone;
b) a plate portion extending from and inseparable from said nail portion, said plate portion having a second length less than one half said first length and having a maximum thickness less than said first diameter, said plate portion provided adjacent said first portion of said nail portion, said plate portion including at least one hole having a longitudinal axis extending through said hole and a countersink portion configured to allow the head portion of the fastener to be countersunk within the plate portion and to fix the fastener within said hole in a fixed angle orientation along said longitudinal axis; and
c) a neck region that connects said plate portion to said first portion of said nail and offsets said plate portion from said first portion of said nail portion so that said plate portion is parallel to but not coaxial with said first portion of said nail portion, said neck region including a threaded hole, and
each of said plate portion and said first portion of said nail portion extend from said neck region in opposite, and not in the same, directions from each other from said neck region.
2. A device according to claim 1 , wherein:
said nail portion has a longitudinal axis, and said second portion of said nail terminates in a section that curves relative to said longitudinal axis.
3. A device according to claim 1 , wherein:
said device has a longitudinal axis in a direction extending from said nail portion to said plate portion, and said plate portion has an upper surface that is convexly curved in a direction transverse to said longitudinal axis.
4. A device according to claim 3 , wherein:
said plate portion has a lower surface that is concavely curved in a direction transverse to said longitudinal axis.
5. A device according to claim 1 , wherein:
said device has a longitudinal axis in a direction extending from said nail portion to said plate portion, and said plate portion has a lower surface that is concavely curved in a direction transverse to said longitudinal axis.
6. A device according to claim 1 , wherein:
said first portion of said nail includes a plurality of threaded screw holes, all extending through said nail in a parallel orientation, and
said plate portion includes a plurality of screw holes, each configured to guide respective fasteners in a discrete axis such that none of the axes defined by the screw holes in the plate portion are parallel.
7. A device according to claim 1 , wherein:
said threaded hole in said neck region is oriented parallel with the at least one threaded screw hole in the first portion of the nail portion.
8. A device according to claim 1 , wherein:
said nail portion is divided equally by length into said first and second portions, and said second portion is absent of any screw holes.
9. A device according to claim 1 , wherein:
said nail portion includes two threaded screw holes and has a longitudinal axis, and said first portion of said nail is non-circular in cross-section transverse to said longitudinal axis at a location between said two threaded screw holes.
10. A device according to claim 1 , wherein:
said nail portion has a longitudinal axis, and said first portion of said nail has a circular cross-section in a direction transverse to said longitudinal axis.
11. A device according to claim 1 , wherein:
said nail portion has a longitudinal axis, and said second portion of said nail portion has a round cross-section in a direction transverse to said longitudinal axis.
12. A device according to claim 11 , wherein:
said second portion of said nail portion has said round cross-section shape along its entire length.
13. A device according to claim 12 , wherein:
said first portion of said nail portion has a round cross-section shape in a direction transverse to said longitudinal axis.
14. A device according to claim 1 , wherein:
said nail portion defines a longitudinal axis, and said plate portion includes three holes configured to guide fasteners, each of said holes aligned on said longitudinal axis and configured to orient a fastener in a discrete fixed angle orientation.
15. A device according to claim 14 , wherein:
each of said three holes is threaded and adapted to receive a fastener with a threaded head.
16. A one-piece bone fracture fixation device for use with a fastener, said device for stabilization of a fracture of a bone of an upper extremity, the bone having a metaphysis and diaphysis, the diaphysis defining a medullary canal, said device comprising:
a) an elongate nail portion having a first length and including a first portion with a first diameter with at least one threaded screw hole extending therein and an opposite second portion having a smaller diameter than said first portion and having a decreased rigidity relative to said first portion thereby permitting the second portion to flex relative to the first portion, an entirety of said nail portion sized to be received within the medullary canal of the bone;
b) a plate portion extending from and inseparable from said nail portion, said plate portion having a second length less than one half said first length and having a maximum thickness less than said first diameter, said plate portion provided adjacent said first portion of said nail portion, said plate portion including at least one hole configured to guide the fastener through said hole in a fixed angle orientation; and
c) a neck region that connects said plate portion to said first portion of said nail and offsets said plate portion from said first portion of said nail portion so that said plate portion is parallel to but not coaxial with said first portion of said nail portion, said neck region including a threaded hole oriented parallel with the at least one threaded screw hole in the first portion of the nail portion, and
each of said plate portion and said first portion of said nail portion extend from said neck region in opposite, and not in the same, directions from each other from said neck region.