Stress fracture, left humerus, subs for fx w malunion

This code signifies a stress fracture affecting the left humerus that is currently undergoing treatment for a malunion. A malunion indicates that the fracture has healed, but in an unsatisfactory position, leading to functional impairment or deformity. This specific code is used for follow-up care related to this malunited stress fracture.

Apply this code when a patient presents for ongoing management, evaluation, or treatment of a previously diagnosed stress fracture of the left humerus that has healed incorrectly. Documentation should clearly state "malunion" and specify the left humerus as the affected site, along with an indication of a subsequent encounter for this condition. This would include scenarios like surgical correction of the malunion, physical therapy for associated functional deficits, or imaging to assess the malunion's stability.

• Ensure documentation explicitly states "malunion" and specifies the left humerus.
• Distinguish from nonunion (M84.322N), where the fracture has not healed at all.
• Verify the encounter type; "P" indicates a subsequent encounter for a fracture with malunion, not initial care.