Unsp fx fourth MC bone, left hand, subs for fx w malunion

This code signifies a fracture of the fourth metacarpal bone in the left hand that was not specified further at the time of initial diagnosis. The patient is in a subsequent phase of care, and the fracture has developed malunion, meaning it has healed in an anatomically incorrect position. This indicates an ongoing treatment episode for a complicated healing process.

Use this code for follow-up encounters where a patient is being treated for a previously diagnosed, unspecified fracture of their left fourth metacarpal, and imaging or clinical assessment confirms that the bone has healed with malunion. This would apply during the period of active management for the malunion, such as planning for corrective surgery or monitoring the functional impact.

• Ensure documentation clearly specifies "left hand" and "fourth metacarpal" and confirms malunion.
• Verify this is a "subsequent encounter" and not an initial treatment or sequela.
• Look for associated procedure codes if surgical correction of the malunion is performed.