Disp fx of shaft of metacarpal bone, subs for fx w nonunion

This code describes a situation where a patient has a fracture in the shaft of a metacarpal bone (excluding the thumb and little finger) that was initially displaced, and the fracture has failed to heal properly, resulting in a nonunion. This indicates a persistent gap or lack of bony bridge formation at the fracture site despite adequate time for healing.

Use this code for follow-up encounters where a previously diagnosed displaced shaft fracture of a metacarpal (other than the first or fifth) is now complicated by nonunion. This applies when the patient is receiving ongoing treatment for the unhealed fracture, such as further surgical intervention or conservative management for the nonunion.

• Always sequence this code after the appropriate external cause code, if applicable.
• Ensure documentation clearly specifies "nonunion" and the specific metacarpal involved (excluding the thumb and little finger).
• Verify the fracture was initially "displaced" as this is a key component of the code.