Oth fx first MC bone, left hand, subs for fx w malunion

This code indicates a fracture of the first metacarpal bone in the left hand, which is currently in a healing phase but has united in an anatomically incorrect or misaligned position. This malunion can lead to functional impairment and pain.

This code is appropriate for follow-up encounters where a previously treated left first metacarpal fracture is now documented as having malunited. It should be used when the patient is receiving ongoing care for the complications or management of this improperly healed fracture.

• Always confirm the laterality (left hand) and the specific bone (first metacarpal).
• Ensure documentation clearly states "malunion" and that it's a "subsequent encounter" for the fracture.
• Do not use this code for initial treatment of a new fracture or for nonunion.