10ICD Code Hub

M21

Header — not billable

Other acquired deformities of limbs

The ICD-10 code for other acquired deformities of limbs is M21.

M21 is a non-billable header code. It groups related conditions but cannot be used on its own for reimbursement — select one of the 10 more specific codes below.

Clinical notes

Excludes1 (not coded here)

An Excludes1 note is a pure exclusion: the excluded condition and this code should never be reported together, because the two conditions cannot occur at the same time (e.g. a congenital form vs. an acquired form of the same disease).

  • acquired absence of limb (Z89.-)
  • congenital absence of limbs (Q71-Q73)
  • congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74)

Excludes2 (not included here)

An Excludes2 note means the excluded condition is not part of this one, but a patient can have both at the same time — in that case both codes may be reported together.

  • acquired deformities of fingers or toes (M20.-)
  • coxa plana (M91.2)

Documentation support

General coding-documentation guidance — not a substitute for payer-specific requirements or professional coding judgment.

Child codes under M21

Related codes in this category