Oth fx unsp patella, subs for opn fx type 3A/B/C w nonunion

This code signifies a non-union of an open patellar fracture, specifically of types IIIA, IIIB, or IIIC, that is being treated in a subsequent encounter. This indicates that the initial fracture treatment was unsuccessful in achieving bone healing, and the patient is now presenting for ongoing management of the unhealed fracture.

This code is appropriate for patients presenting for follow-up care, surgical intervention, or other management related to a previously diagnosed open patellar fracture (type IIIA, IIIB, or IIIC) that has failed to heal. It should be used when documentation clearly indicates nonunion of the fracture.

• Ensure documentation specifies the open fracture type (IIIA, IIIB, or IIIC) and explicitly states "nonunion."
• Verify that this is a subsequent encounter for the fracture, not the initial treatment.
• Always sequence this code with any associated external cause codes and other relevant injury codes.