Stress fracture, right humerus, subs for fx w malunion

This code signifies a stress fracture affecting the right humerus that has healed incorrectly, resulting in a malunion. The patient is currently receiving follow-up care for this previously treated fracture.

Apply this code when documentation indicates a patient is being seen for ongoing management or treatment of a right humeral stress fracture that has healed in a misaligned position. This typically occurs in a post-operative or follow-up setting after initial fracture treatment.

• Ensure documentation explicitly states "malunion" and specifies the "right humerus" for accurate coding.
• Verify that the encounter is for follow-up care, not initial treatment, as indicated by "subsequent encounter."
• Distinguish from nonunion (M84.4-) where the fracture has not healed at all, versus malunion where it has healed incorrectly.