Plate and cannulated transfixation screw system for human implant

A screw, comprising:

• an elongate hollow body having openings at first and second ends and having a tip at the first end and a head at the second end;
• a first thread originating from the tip and extending proximate to the tip, the first thread having a first pitch;
• a second thread disposed proximate to the head and having a second pitch, the second pitch being different than the first pitch;
• and
• a locking thread disposed on the head and having a third pitch.

A screw for securing first and second bones together across a joint, comprising:

• an elongate hollow body having openings at first and second ends and having a tip at the first end and a head at the second end;
• a first thread originating proximate the tip and extending proximally from the tip, the first thread having a first pitch;
• a second thread disposed proximate the head, extending distally from the head and having a second pitch, the second pitch being different than the first pitch;
• and
• a locking thread disposed on the head and having a third pitch,
• wherein the screw is configured to extend from the first bone across the joint into the second bone to secure the second bone at an angle between 20 and 50 degrees relative to the first bone.

A system for securing first and second bones together across a joint, comprising:

• a fixation plate having a body, said body having a longitudinal axis and first and second ends, the body configured to be placed upon a bone and reside on one side of a joint, the body having a locking screw hole disposed proximate to the first end, a central axis through the locking screw hole oriented at a first angle between 20 to 50 degrees relative to the longitudinal axis, the body having at least one attachment screw hole;
• and
• a screw having an elongate hollow body, said body having openings at first and second ends and having a tip at the first end and a head at the second end, the body configured to extend through the first bone across the joint and into the second bone, the head configured to abut the locking screw hole,
• said screw further including:
• a first thread originating proximate the tip and extending proximally to the tip, the first thread having a first pitch;
• a second thread disposed proximate to the head, extending distally from the head and having a second pitch, the second pitch being different than the first pitch;
• and
• a locking thread disposed on the head and having a third pitch, the locking thread configured to engage the locking screw hole.

A system for securing first and second bones together across a joint, comprising:

• a fixation plate configured to be placed upon the first bone and reside on one side of the joint, the fixation plate comprising:
• a body having a longitudinal axis and first and second ends, the body having a locking screw hole disposed proximate to the first end, an inner surface of the locking screw hole having an upper countersink, a lower countersink and a threaded portion between the upper and lower countersinks, the threaded portion having double helical threads, a central axis through the locking screw hole being oriented at an angle between 20 to 50 degrees relative to the longitudinal axis, the body having at least one attachment screw hole;
• and
• a screw comprising:
• an elongate hollow body having openings at first and second ends and having a tip at the first end and a head at the second end, the body configured to extend through the first bone across the joint and into the second bone, the head configured to abut the locking screw hole;
• a first thread originating proximate the tip and extending proximally from the tip, the first thread having a first pitch;
• a second thread disposed proximate to the head and having a second pitch, the second pitch being different than the first pitch;
• and
• a locking thread disposed on the head and having a third pitch, the locking thread configured to engage the double helical threads on the locking screw hole when the screw is inserted through the locking screw hole,
• wherein the second bone is positioned at an angle between 20 and 50 degrees relative to the longitudinal axis.