Intramedullary nail with locking key
View Patent ↗An intramedullary nail comprises longitudinal channel, a first transverse passage and a second transverse passage. A lag screw extends through the first transverse passage of the intramedullary nail. An anti-rotation shaft extends through the second transverse passage of the intramedullary nail. A cannulated lag screw lock is positioned in the intramedullary shaft and engages the lag screw. The anti-rotation shaft extends through a cross channel in the lag screw lock. A second shaft lock is positioned in the intramedullary nail with the second shaft lock engaging the anti-rotation shaft. In at least one embodiment, the lag screw lock includes a substantially cylindrical body portion rotatably connected to a threaded head portion. In at least one embodiment, the second shaft lock is provided as an end cap including a threaded upper portion and a lower post portion that extends into the lag screw lock.
1. An intramedullary nail assembly comprising:
an intramedullary shaft including a longitudinal channel, a first transverse passage and a second transverse passage, wherein the first transverse passage is configured to receive a lag screw and wherein the second transverse passage is configured to receive an anti-rotation shaft;
a cannulated lag screw lock member positioned in the longitudinal channel of the intramedullary shaft, the lag screw lock member including a longitudinal passage and a locking surface, wherein the longitudinal passage extends through the lag screw lock member and is open to the longitudinal channel of the intramedullary shaft, and wherein the locking surface is configured to engage the lag screw and prohibit rotation of the lag screw in the first transverse passage; and
a cap positioned in the longitudinal channel of the intramedullary shaft, the cap including a locking surface configured to engage the anti-rotation shaft and prohibit rotation of the anti-rotation shaft in the second transverse passage;
wherein:
the lag screw lock member includes a substantially cylindrical body portion rotatably connected to a threaded head portion, the cylindrical body portion and the threaded head portion defining the longitudinal passage;
the cylindrical body portion includes the locking surface of the lag screw lock member and defines a cross slot aligned with the second transverse passage in the intramedullary shaft, the cross slot being configured to receive the anti-rotation shaft; and
the threaded head portion engages complimentary threads in the longitudinal channel of the intramedullary shaft such that rotation of the threaded head portion results in movement of the cylindrical body portion along a longitudinal axis of the intramedullary shaft;
wherein:
the cap includes a threaded upper portion and a lower post portion, the lower post portion including the locking surface of the cap;
the threaded upper portion of the cap engages the complimentary threads in the longitudinal channel of the intramedullary shaft;
the lower post portion extends into the longitudinal passage to position the locking surface of the cap proximate the cross slot; and
a thread lock,
wherein:
the longitudinal channel of the intramedullary shaft defines a longitudinal groove that cuts across and into the complimentary threads on an upper portion of the intramedullary nail, the thread lock being positioned in the longitudinal groove such that it engages both (1) the threaded head portion of the lag screw lock member and resists rotation of the threaded head portion relative to the complimentary threads, and (2) the threaded upper portion of the cap.
2. The assembly of claim 1 , further comprising:
a lag screw received in the first transverse channel.
3. The assembly of claim 2 , wherein the lag screw includes a plurality of suture holes.
4. The assembly of claim 1 , further comprising:
an anti-rotation shaft received in the second transverse channel.
5. The assembly of claim 1 , wherein the cap includes an uppermost portion opposite the locking surface, the uppermost portion at least partially disposed in the longitudinal channel of the intramedullary shaft.