Implant system for bone fixation

An implant system for fixation of a long bone, comprising:

• an intramedullary nail having an axial bore and a transverse bore intersecting the axial bore, the axial bore having a threaded inner surface and defining a first central axis, the transverse bore defining a second central axis oriented at an oblique angle relative to the first central axis;
• a lag screw having a longitudinally extending groove formed in an exterior thereof, the lag screw located in the transverse bore;
• a coupling member having a drive portion, an engagement portion integrally formed with the drive portion, and a through hole extending through the drive portion and engagement portion, the through hole defining a third central axis, the drive portion having a thread configured to engage the threaded inner surface of the axial bore, the engagement portion having a cylindrical outer surface, a planar end surface, and a contact surface extending therebetween, the cylindrical outer surface having a diameter extending perpendicular to the third central axis, and the planar end surface having a maximum dimension extending perpendicular to the third central axis, the diameter of the cylindrical outer surface being greater than the maximum dimension of the planar end surface, and
• wherein, when the coupling member is advanced to a maximum extent toward the lag screw while within the axial bore of the intramedullary nail, a portion of the contact surface of the coupling member is received within the groove to prevent rotation of the lag screw;
• and
• wherein the threaded inner surface of the axial bore for engaging with the coupling member longitudinally extends towards and ends at the intersection of the axial bore with the transverse bore.

An implant system for fixation of a long bone, comprising:

• an intramedullary nail having an axial bore and a transverse bore intersecting the axial bore, the axial bore having a threaded inner surface and defining a first central axis, the transverse bore defining a second central axis oriented at an oblique angle relative to the first central axis;
• a lag screw defining a third central axis and having a longitudinally extending groove defining an inner surface and a first arc segment in a plane perpendicular to the second central axis, the lag screw located in the transverse bore;
• and
• a coupling member having a drive portion, an engagement portion extending from the drive portion, and a through hole extending through the drive portion and engagement portion, the through hole defining a fourth central axis, the drive portion having a thread for engagement with the threaded inner surface of the axial bore, the engagement portion having a peripheral surface, a planar end surface, and a contact surface extending therebetween, the contact surface extending about the fourth central axis and having a portion thereof that defines a second arc segment,
• wherein the first arc segment and second arc segment define substantially equal curvatures such that the second arc segment contacts the first arc segment along an entirety of the first arc segment's length when the coupling member is fully advanced through the bore and the contact surface engages the inner surface of the lag screw;
• and
• wherein the threaded inner surface of the axial bore for engaging with the coupling member longitudinally extends towards and ends at the intersection of the axial bore with the transverse bore.