Unsp fx upr end l ulna, subs for opn fx type I/2 w nonunion

This code signifies a non-healing fracture of the upper portion of the left ulna, where the specific type of fracture was not documented at the initial injury. This particular encounter is for ongoing management of an open fracture, specifically Gustilo type I or II, that has failed to unite.

This code is appropriate for follow-up encounters when a patient with a previously diagnosed, unspecified fracture of the proximal left ulna presents with evidence of nonunion. It specifically applies when the original injury was an open fracture classified as Gustilo type I or II, and the current visit addresses the continued lack of healing.

• Ensure documentation clearly states "nonunion" and specifies the left ulna's upper end.
• Verify the original injury was an open fracture, Gustilo type I or II, even if the initial fracture type was unspecified.
• This code requires an additional code for the specific type of nonunion (e.g., M84.422A).