T24.729A Corrosion of third degree of unspecified knee, initial encounter

Billable ICD-10-CM code, FY2026.

Built from T24.729 with 7th character A (initial encounter).

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 T24.7 Corrosion of third 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)

Medicare Code Edits (MCE v43.1 (April 2026))

• Unspecified code (laterality): Unspecified codes for which a more specific code identifying laterality (right, left, bilateral) exists within the same code family.

Code annotations containing back-references to T24.729A

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 T24.729A

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

Nearby codes

• T24.722 Corrosion of third degree of left knee
• T24.722A Corrosion of third degree of left knee, initial encounter
• T24.722D Corrosion of third degree of left knee, subsequent encounter
• T24.722S Corrosion of third degree of left knee, sequela
• T24.729 Corrosion of third degree of unspecified knee
• T24.729A Corrosion of third degree of unspecified knee, initial encounter (this code)
• T24.729D Corrosion of third degree of unspecified knee, subsequent encounter
• T24.729S Corrosion of third degree of unspecified knee, sequela
• T24.73 Corrosion of third degree of lower leg
• T24.731 Corrosion of third degree of right lower leg
• T24.731A Corrosion of third degree of right lower leg, initial encounter