Pathological fracture, right humerus, subs for fx w nonunion

This code signifies a fracture of the right humerus that occurred due to an underlying disease process, rather than trauma, and has failed to heal properly. The patient is currently receiving routine care during the healing phase for this nonunion.

Apply this code when documentation indicates a pathological fracture of the right humerus with confirmed nonunion, and the patient is presenting for follow-up care, cast changes, or medication management related to the fracture's healing. This code is appropriate after the initial treatment of the fracture has been completed.

• Ensure documentation clearly states "pathological fracture" and "nonunion" of the right humerus.
• Distinguish from malunion (M84.421P) or routine healing (M84.421D, M84.421G, M84.421S).
• Always sequence the underlying disease causing the pathological fracture first, if known and still active.