M21
ICD-10Non-billable categoryOther acquired deformities of limbs
Official ICD-10-CM descriptor (FY2026)
Other acquired deformities of limbs
M21 is a category heading, not a billable code. CMS does not accept it on a claim; report one of the more specific codes beneath it.
Excludes1
Not coded here. An Excludes1 code should never be reported at the same time as the code above it.
- 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. The condition is not part of this code, but a patient may have both, and both codes may be reported together.
- acquired deformities of fingers or toes (M20.-)
- coxa plana (M91.2)
More specific codes under M21
- M21.0Valgus deformity, not elsewhere classifiedcategory
- M21.1Varus deformity, not elsewhere classifiedcategory
- M21.2Flexion deformitycategory
- M21.3Wrist or foot drop (acquired)category
- M21.4Flat foot [pes planus] (acquired)category
- M21.5Acquired clawhand, clubhand, clawfoot and clubfootcategory
- M21.6Other acquired deformities of footcategory
- M21.7Unequal limb length (acquired)category
- M21.8Other specified acquired deformities of limbscategory
- M21.9Unspecified acquired deformity of limb and handcategory
Where this code sits
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ICD-10-CM FY2026. Centers for Medicare & Medicaid Services (CMS) / National Center for Health Statistics (NCHS), “2026 ICD-10-CM Code Descriptions in Tabular Order” (icd10cm_order_2026.txt). Download the original file from cms.gov. Public domain (US Government work). Descriptors, billable flags and instructional notes on this page are reproduced from that file without modification. Krasyn adds no clinical guidance.