M21 ICD-10-CM Code: Other acquired deformities of limbs
A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.
Official description
M21Other acquired deformities of limbs
ICD-10-CM diagnosis code · United States clinical modification
Where M21 sits
- 1
Chapter 13
Diseases of the musculoskeletal system and connective tissue (M00-M99)
- 2
Section
Other joint disorders (M20-M25)
- 3
Category M21
Other acquired deformities of limbs
- 4
Code M21
Other acquired deformities of limbs
Codes under M21
M21 is a non-billable category. Choose the child code that best matches the documented diagnosis.
M21.0Valgus deformity, not elsewhere classifiedM21.1Varus deformity, not elsewhere classifiedM21.2Flexion deformityM21.3Wrist or foot drop (acquired)M21.4Flat foot [pes planus] (acquired)M21.5Acquired clawhand, clubhand, clawfoot and clubfootM21.6Other acquired deformities of footM21.7Unequal limb length (acquired)M21.8Other specified acquired deformities of limbsM21.9Unspecified acquired deformity of limb and handNotes for this code
Inclusion terms
No inclusion terms are listed for M21.
Code first
No “code first” instruction is listed for M21.
Use additional code
No “use additional code” instruction is listed for M21.
Excludes1
Conditions that should not be reported together with this code.
- acquired absence of limb (Z89.-)
- congenital absence of limbs (Q71-Q73)
- congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74)
Excludes2
Conditions not included here that may be reported separately when present.
- acquired deformities of fingers or toes (M20.-)
- coxa plana (M91.2)
Source and release
- Data release
- U.S. ICD-10-CM · FY 2027
- Effective date
- Oct 1, 2026
- Publisher
- Vero Scribe Inc.
This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.
Frequently asked questions
What does ICD-10-CM code M21 mean?
M21 is the FY 2027 U.S. ICD-10-CM code for “Other acquired deformities of limbs.”
Is M21 a billable or specific ICD-10-CM code?
No. M21 has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.
Where is M21 located in ICD-10-CM?
M21 is listed in Chapter 13, Diseases of the musculoskeletal system and connective tissue (M00-M99), within Other joint disorders (M20-M25) (M20–M25), under category M21, Other acquired deformities of limbs.
What coding notes are listed for M21?
No inclusion terms are listed for M21 in this reference record. No code-first instruction is listed. Excludes1 notes: acquired absence of limb (Z89.-); congenital absence of limbs (Q71-Q73); congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74). Excludes2 notes: acquired deformities of fingers or toes (M20.-); coxa plana (M91.2).