T24.421S Corrosion of unspecified degree of right knee, sequela

Billable ICD-10-CM code, FY2026.

Built from T24.421 with 7th character S (sequela).

Applies from T24 Burn and corrosion of lower limb, except ankle and foot

Excludes2 (not included here)

• burn and corrosion of ankle and foot (T25.-)
• burn and corrosion of hip region (T21.-)

7th character note

• The appropriate 7th character is to be added to each code from category T24

7th character required

• A — initial encounter
• D — subsequent encounter
• S — sequela

Applies from T24.4 Corrosion of unspecified degree of lower limb, except ankle and foot

Code first

• (T51-T65) to identify chemical and intent

Use additional code

• external cause code to identify place (Y92)

Code annotations containing back-references to T24.421S

Back-references to T24

• Type 1 Excludes: T66 Radiation sickness, unspecified ("burns (T20-T31)")
• Type 2 Excludes: T67 Effects of heat and light ("burns (T20-T31)")
• Type 2 Excludes: T75 Other and unspecified effects of other external causes ("burns (electric) (T20-T31)")

Diagnosis Index entries for T24.421S

• Corrosion (injury) (acid) (caustic) (chemical) (lime) (external) (internal) › knee › right

Nearby codes

• T24.419S Corrosion of unspecified degree of unspecified thigh, sequela
• T24.42 Corrosion of unspecified degree of knee
• T24.421 Corrosion of unspecified degree of right knee
• T24.421A Corrosion of unspecified degree of right knee, initial encounter
• T24.421D Corrosion of unspecified degree of right knee, subsequent encounter
• T24.421S Corrosion of unspecified degree of right knee, sequela (this code)
• T24.422 Corrosion of unspecified degree of left knee
• T24.422A Corrosion of unspecified degree of left knee, initial encounter
• T24.422D Corrosion of unspecified degree of left knee, subsequent encounter
• T24.422S Corrosion of unspecified degree of left knee, sequela
• T24.429 Corrosion of unspecified degree of unspecified knee