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M21Non-billableSave

M21 - Other acquired deformities of limbs

ICD-10-CM Chapter 13: Diseases of the musculoskeletal system and connective tissue · M20-M25 Other joint disorders (M20-M25) · Top-level category · FY2027

Coding Guidance

M21 is a non-billable heading. Report one of the 10 more specific codes below.

Includes, Excludes and Coding Notes

Excludes 1 — Not Coded HereFrom M21

Mutually exclusive: these conditions are never 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)
Excludes 2 — Not Included HereFrom M21

Not part of this code; report both codes when the patient has both conditions.

  • acquired deformities of fingers or toes (M20.-)
  • coxa plana (M91.2)
Excludes 2 — Not Included HereFrom M20-M25 Other joint disorders (M20-M25)

Not part of this code; report both codes when the patient has both conditions.

  • joints of the spine (M40-M54)
Excludes 2 — Not Included HereFrom Chapter M00-M99

Not part of this code; report both codes when the patient has both conditions.

  • arthropathic psoriasis (L40.5-)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • compartment syndrome (traumatic) (T79.A-)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
NotesFrom Chapter M00-M99

Instructional notes from the ICD-10-CM tabular list.

  • Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition

More Specific Codes (10)

M21.0Valgus deformity, not elsewhere classified→M21.1Varus deformity, not elsewhere classified→M21.2Flexion deformity→M21.3Wrist or foot drop (acquired)→M21.4Flat foot [pes planus] (acquired)→M21.5Acquired clawhand, clubhand, clawfoot and clubfoot→M21.6Other acquired deformities of foot→M21.7Unequal limb length (acquired)→M21.8Other specified acquired deformities of limbs→M21.9Unspecified acquired deformity of limb and hand→

Related condition guides

Documentation requirements, coding pitfalls and FAQs for conditions coded with M21.