Disp fx of base of unsp MC bone, subs for fx w nonunion

This code signifies a fracture at the base of any metacarpal bone that has shifted out of its normal alignment and is currently in a stage of healing where the bone fragments have failed to unite after a typical healing period. This diagnosis indicates a complication in the fracture's recovery process, specifically a nonunion, and the patient is presenting for follow-up care related to this ongoing issue.

Apply this code when a patient with a previously diagnosed displaced fracture of an unspecified metacarpal base returns for treatment or evaluation of a confirmed nonunion. This is appropriate for subsequent visits where the primary focus is managing the delayed or failed bone healing. It would be used for scenarios such as casting changes, physical therapy, or surgical planning for the nonunion.

• Ensure documentation clearly states "nonunion" and specifies the "base" of the metacarpal.
• Confirm the encounter is "subsequent" and not the initial treatment for the fracture.
• If the specific metacarpal bone (e.g., first, second) is known, a more specific code should be used.