Bone screw with self-constrained flexibility

A method of assembling a bone screw, the method comprising:

• selecting a longitudinal core member defining a longitudinal axis and that comprises having an outer surface and a helical groove in the outer surface, the helical groove being defined by opposed sidewalls and a bottom surface between the opposed sidewalls;
• selecting a helical thread body configured to be accommodated in the helical groove;
• and
• screwing the helical thread body onto the core member,
• wherein, when the thread body is assembled in the helical groove of the core member and when the core member is straight along the longitudinal axis, the thread body is configured to abut one opposed sidewall without abutting the other opposed sidewall along a full turn of the thread body,
• wherein, when the thread body and the core member are assembled, a first portion of the thread body that is outside the helical groove has a height greater than a second portion of the thread body that is in the helical groove, and
• wherein the thread body is configured to slide in the groove between the opposed sidewalls of the helical groove in a direction parallel to the longitudinal axis.

A method of inserting a bone screw into a bond, the bone screw comprising a longitudinal core member defining a longitudinal axis and having an outer surface and a helical groove in the outer surface, the helical groove being defined by opposed sidewalls and a bottom surface between the opposed sidewalls;

• and a helical thread body configured to be accommodated in the helical groove, wherein , when the thread body is assembled in the helical groove of the core member and when the core member is straight along the longitudinal axis, the thread body is configured to abut one opposed sidewall without abutting the other opposed sidewall along a full turn of the thread body, and wherein, when the thread body and the core member are assembled, a first portion of the thread body that is outside the helical groove has a height greater than a second portion of the thread body that is in the helical groove, and wherein the thread body is configured to slide in the groove between the opposed sidewalls of the helical groove in a direction parallel to a longitudinal axis, the method comprising:
• preparing a core hole in the bone;
• and
• inserting the longitudinal core member with the thread body assembled in the helical groove of the core member into the core hole.