Stress fracture, unsp ankle, subs for fx w nonunion

This code signifies a stress fracture affecting an unspecified ankle that has failed to heal properly (nonunion) and is being treated in a subsequent encounter. A stress fracture is a tiny crack in a bone caused by repetitive stress or overuse, rather than a single traumatic event. Nonunion indicates that the bone ends have not grown together after a prolonged period.

Use this code when a patient presents for ongoing management or treatment of an ankle stress fracture that has been previously diagnosed and is now complicated by nonunion. Documentation should clearly state "stress fracture," "ankle" (without specifying left or right), "nonunion," and indicate that this is not the initial treatment encounter for the fracture.

• Ensure documentation specifies "stress fracture" versus a traumatic fracture; traumatic fractures have different coding pathways.
• Verify the laterality of the ankle is truly unspecified in the documentation; if left or right is documented, a more specific code should be used.
• Confirm the "subsequent encounter" and "nonunion" status are explicitly documented to support the 7th character and the nonunion designation.