Coding and coverage · ICD-10-CM

S90 › S90.5

S90.54 External constriction of ankle

Not billable (header)Chapter 19

This code needs a 7th character (use X as a placeholder for missing characters).

Codes under this one

  • S90.541 External constriction, right ankleHeader
  • S90.542 External constriction, left ankleHeader
  • S90.549 External constriction, unspecified ankleHeader

Instructional notes

Chapter 19

Excludes2Not included here: the patient may have both; report both when both are present.
Use additional codeAdd a second code for the full picture.
  • code to identify any retained foreign body, if applicable (Z18.-)
Notes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

Section S90-S99

Excludes2Not included here: the patient may have both; report both when both are present.
  • burns and corrosions (T20-T32)
  • fracture of ankle and malleolus (S82.-)
  • frostbite (T33-T34)
  • insect bite or sting, venomous (T63.4)

S90

7th charactersThe appropriate 7th character is to be added to each code from category S90
  • A initial encounter
  • D subsequent encounter
  • S sequela

Chapter 19: Injury, poisoning and certain other consequences of external causes · S90-S99 Injuries to the ankle and foot (S90-S99)

Source: ICD-10-CM FY 2027 code descriptions and tabular list (CMS and CDC National Center for Health Statistics), effective 2026-10-01 through 2027-09-30 · CMS ICD-10 files. HCC mapping: CMS-HCC V28, payment year 2027. As of 2026-11-04.

Coverage and payment depend on the claim details; confirm with the Medicare Administrative Contractor.