Unsp fx unsp low leg, subs for opn fx type 3A/B/C w nonunion

This code signifies a fracture of an unspecified part of the lower leg, where the specific bone or location is not documented. It is used for a subsequent encounter when the initial open fracture was classified as type IIIA, IIIB, or IIIC (indicating significant soft tissue damage and contamination), and the fracture has failed to heal properly (nonunion).

This code is appropriate for follow-up visits where a patient is being treated for a previously diagnosed severe open lower leg fracture that has not united. This includes scenarios where surgical intervention for nonunion is being planned or has been performed, or during ongoing conservative management of the nonunion.

• Ensure documentation clearly states "nonunion" and specifies a subsequent encounter for an open fracture type IIIA, IIIB, or IIIC.
• Avoid using this code if a more specific lower leg bone (e.g., tibia, fibula) or location is documented; instead, use the appropriate specific fracture code.
• Always sequence this code after any codes for external causes of injury or complications, if applicable.