Spiral U-blade lag screw
A lag screw assembly includes a lag screw and a blade. The lag screw includes a shank extending from a proximal end to a distal end along a longitudinal axis, the shank having an outer surface, and the shank having a threaded portion at the distal end. The lag screw further includes a groove formed in the shank and open to the outer surface, the groove extending along the shank between the proximal and distal ends. At least a portion of the groove defines a path that extends around and along the longitudinal axis on the outer surface. The blade has a head and a leg extending therefrom for slidably engaging the groove.
1 . A lag screw assembly comprising:
a lag screw including:
a shank extending from a proximal end to a distal end along a longitudinal axis, the shank having an outer surface, and the shank having a threaded portion at the distal end;
a groove formed in the shank and open to the outer surface, the groove extending along the shank between the proximal and distal ends,
wherein at least a portion of the groove defines a path that extends around and along the longitudinal axis on the outer surface; and
a blade having a head and a leg extending therefrom for slidably engaging the groove, at least a portion of the leg protruding farther in a radial direction than an outer diameter of the threaded portion,
wherein an outer surface of the leg defines an indentation.
2 . The lag screw assembly of claim 1 , wherein the groove extends along the shank in a helical path.
3 . The lag screw assembly of claim 2 , wherein the leg of the blade is adapted to extend along the shank in the helical path.
4 . The lag screw assembly of claim 1 , wherein the groove extends into the threaded portion of the shank.
5 . The lag screw assembly of claim 1 , wherein the head of the blade is an annular cylindrical portion and the leg is integral with the annular cylindrical portion, and wherein the head of the blade is adapted to be fastened to the proximal end of the shank with a fastener.
6 . The lag screw assembly of claim 5 , further comprising a screw configured to be threadably coupled to the head of the blade and the proximal end of the shank.
7 . The lag screw assembly of claim 1 , wherein a depth of the groove varies along a length of the shank.
8 . The lag screw assembly of claim 7 , wherein the groove defines a first depth at the threaded portion of the shank and a second depth at a non-threaded portion of the shank, the second depth being greater than the first depth.
9 . The lag screw assembly of claim 1 , wherein the lag screw includes a recess at the proximal end for engaging a tool.
10 . The lag screw assembly of claim 1 , wherein the groove extends from the proximal end of the shank to the distal end of the shank.
11 . The lag screw assembly of claim 1 , wherein an outer diameter of the head substantially corresponds in size to an outer diameter of the screw shank.
12 . The lag screw assembly of claim 1 , wherein at least a portion of the leg is adapted to follow the path defined by the groove as the portion of the leg extends along the shank.
13 . The lag screw assembly of claim 1 , wherein the groove formed in the shank is a first groove, and the lag screw includes a second groove formed in the shank and open to the outer surface, the second groove extending along the shank between the proximal end and the distal end.
14 . The assembly of claim 13 , wherein at least a portion of one of the first groove and the second groove has a depth substantially equal to a thickness of the blade.
15 . The assembly of claim 13 , wherein the first and second grooves extend into the threaded portion, and wherein when the blade is coupled to the shank, a portion of the blade corresponding to the threaded portion extends outwardly from at least one of the first and second grooves in the threaded portion a distance greater than a root diameter of a thread of the threaded portion.
16 . The assembly of claim 1 , wherein a first portion of the leg protrudes farther from the groove in the radial direction than a second portion of the leg.
17 . A fixation assembly for fixation of a bone, comprising:
an intramedullary nail defining a bore therethrough; and
the lag screw assembly of claim 1 configured to extend through the bore of the intramedullary nail.
18 . The assembly of claim 17 , wherein the bore defined by the intramedullary nail is substantially cylindrical, sized to receive the lag screw, and includes at least a groove configured to receive the leg of the blade therethrough, wherein the leg is protruding from a circumference of the shank when coupled to the shank.
19 . A lag screw assembly comprising:
a lag screw including:
a shank extending from a proximal end to a distal end along a longitudinal axis, the shank having an outer surface, and the shank having a threaded portion at the distal end;
a groove formed in the shank and open to the outer surface, the groove extending along the shank between the proximal and distal ends,
wherein at least a portion of the groove defines a helical path on the outer surface; and
a blade having a head and a leg extending therefrom for slidably engaging the groove,
wherein at least a portion of the leg positioned within a portion of the groove defined in the threaded portion protrudes radially beyond an outer diameter of the threaded portion,
wherein an outer surface of the leg defines an indentation.
20 . A kit for fixation of a bone, comprising:
a lag screw including:
a shank extending from a proximal end to a distal end along a longitudinal axis, the shank having an outer surface, and the shank having a threaded portion at the distal end;
a groove formed in the shank and open to the outer surface, the groove extending along the shank between the proximal and distal ends,
wherein at least a portion of the groove defines a helical path on the outer surface; and
a blade having a head and a leg extending therefrom for slidably engaging the groove,
wherein at least a portion of the blade corresponding to the threaded portion of the shank protrudes radially beyond an outer diameter of the threaded portion, and
wherein an outer surface of the leg defines an indentation.