The most correct Diagnosis Code would be T81.32XA for the deep wound dehiscence, even though traumatic from the fall. The Seventh Character A is for Initial Encounter, even though the patient is within the Global Period from her primary procedure (TKA). I don't think that any of the codes from the Integumentary System for Incision, Drainage, Debridement, or Wound Repair would apply, despite the traumatic origin of the problem. The most appropriate Orthopedic Code would be 27310: Arthrotomy of the Knee Joint with Exploration, Debridement, and (in this case) Evacuation of the Hematoma/Hemarthrosis, with Modifier 78 for Unplanned Return to OR for a Related Procedure During the Postoperative Period. Also, and as usual, send a copy of the Operative Report for documentation.
I hope this helps.
Respectfully submitted, Alan Pechacek, M.D.
icd10orthocoder.com