Bone plate with form-fitting variable-angle locking hole

A system comprising:

• a bone plate including:
• an inner surface configured to face the underlying bone, and an outer surface opposite the inner surface;
• and
• an internal surface that extends from the outer surface to the inner surface so as to define a hole that is oriented along a central hole axis, wherein the internal surface includes 1) a plurality of threaded regions that define respective columns of thread segments, and 2) a plurality of recessed surfaces that are disposed between respective adjacent ones of the thread segments, the recessed surfaces being offset radially outward with respect to the columns of thread segments;
• and
• a variable angle locking screw having a threaded head,
• wherein the bone plate is configured to mate with the threaded head of the variable angle locking screw in the hole at an angle within a range of angles, such that the threaded head threadedly purchases with all of the columns of thread segments, and wherein the angle is oblique to the central hole axis, and
• wherein the thread angle of the thread segments of the bone plate and the thread angle of the threaded head of the bone screw define a ratio between 1.1:1 and approximately 1.8:1.