S99.9Unspecified injury of ankle and foot

S99.9 is the ICD-10-CM diagnosis code for unspecified injury of ankle and foot. It belongs to category S99 (other and unspecified injuries of ankle and foot), block S90-S99 (injuries to the ankle and foot) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is a header code, so it can't be reported by itself; one of its 2 subcodes must be used instead.

Within S99, choose S99.9 (Unspecified injury of ankle and foot) only when documentation doesn't support a more specific option: physeal fracture of calcaneus (S99.0), physeal fracture of metatarsal (S99.1), physeal fracture of phalanx of toe (S99.2) and other specified injuries of ankle and foot (S99.8).

Codes in this range require a 7th character: A for initial encounter, D for subsequent encounter and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.