2020 ICD-10-CM Diagnosis Code M21.4

Flat foot [pes planus] (acquired)

    2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
  • M21.4 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
  • The 2020 edition of ICD-10-CM M21.4 became effective on October 1, 2019.
  • This is the American ICD-10-CM version of M21.4 - other international versions of ICD-10 M21.4 may differ.
Type 1 Excludes
Type 1 Excludes Help
A type 1 excludes note is a pure excludes. It means "not coded here". A type 1 excludes note indicates that the code excluded should never be used at the same time as M21.4. A type 1 excludes note is for used for when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
  • congenital pes planus (
    ICD-10-CM Diagnosis Code Q66.5

    Congenital pes planus

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Applicable To
    • Congenital flat foot
    • Congenital rigid flat foot
    • Congenital spastic (everted) flat foot
    Type 1 Excludes
    • pes planus, acquired (M21.4)
    Q66.5-
    )
The following code(s) above M21.4 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to M21.4:
  • M00-M99
    2020 ICD-10-CM Range M00-M99

    Diseases of the musculoskeletal system and connective tissue

    Note
    • Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
    Type 2 Excludes
    • 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)
    Diseases of the musculoskeletal system and connective tissue
  • M20-M25
    2020 ICD-10-CM Range M20-M25

    Other joint disorders

    Type 2 Excludes
    Other joint disorders
  • M21
    ICD-10-CM Diagnosis Code M21

    Other acquired deformities of limbs

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • acquired absence of limb (Z89.-)
    • congenital absence of limbs (Q71-Q73)
    • congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74)
    Type 2 Excludes
    • acquired deformities of fingers or toes (M20.-)
    • coxa plana (M91.2)
    Other acquired deformities of limbs
Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
Code annotations containing back-references to M21.4:
  • Type 1 Excludes: Q66.5
    ICD-10-CM Diagnosis Code Q66.5

    Congenital pes planus

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Applicable To
    • Congenital flat foot
    • Congenital rigid flat foot
    • Congenital spastic (everted) flat foot
    Type 1 Excludes
    • pes planus, acquired (M21.4)

Diagnosis Index entries containing back-references to M21.4:
  • Deformity Q89.9
    ICD-10-CM Diagnosis Code Q89.9

    Congenital malformation, unspecified

      2016 2017 2018 2019 2020 Billable/Specific Code POA Exempt
    Applicable To
    • Congenital anomaly NOS
    • Congenital deformity NOS
    • limb (acquired) M21.90
      ICD-10-CM Diagnosis Code M21.90

      Unspecified acquired deformity of unspecified limb

        2016 2017 2018 2019 2020 Billable/Specific Code
      • flat foot M21.4-

ICD-10-CM Codes Adjacent To M21.4
M21.279 Flexion deformity, unspecified ankle and toes
M21.3 Wrist or foot drop (acquired)
M21.33 Wrist drop (acquired)
M21.331 Wrist drop, right wrist
M21.332 Wrist drop, left wrist
M21.339 Wrist drop, unspecified wrist
M21.37 Foot drop (acquired)
M21.371 Foot drop, right foot
M21.372 Foot drop, left foot
M21.379 Foot drop, unspecified foot
M21.4 Flat foot [pes planus] (acquired)
M21.40 …… unspecified foot
M21.41 …… right foot
M21.42 …… left foot
M21.5 Acquired clawhand, clubhand, clawfoot and clubfoot
M21.51 Acquired clawhand
M21.511 …… right hand
M21.512 …… left hand
M21.519 …… unspecified hand
M21.52 Acquired clubhand
M21.521 …… right hand

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.