Final answer:
The appropriate ICD-10-CM code for a follow-up visit for a malunited Salter-Harris type 2 fracture of the humerus is S49.021D.
Step-by-step explanation:
The correct code for a Salter-Harris type 2 fracture of the upper end of the humerus that is being seen for follow-up surgery due to a malunion is S49.021D. Salter-Harris fractures are fractures through the growth plates in children, and type 2 fracture involves both the growth plate and the metaphysis. The letter at the end of the code indicates the encounter. 'A' signifies initial encounter for closed fracture, 'B' is initial encounter for open fracture, 'D' is subsequent encounter for fracture with routine healing, 'P' is subsequent encounter with malunion, and 'S' is sequela. Given the scenario includes follow-up surgery for a malunion, the main answer in this case would be S49.021D.
Salter-Harris fractures are a classification system used to describe fractures that involve the growth plate in children and adolescents. A type 2 fracture involves a fracture through the growth plate and a metaphyseal fracture. In this case, the fracture occurred at the upper end of the humerus, and it is being treated with follow-up surgery due to a malunion.