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  6. 2024 ICD-10-CM Code M21.4
Version 2024
Non-Billable Code

2024 ICD-10-CM Diagnosis Code M21.4

Flat foot [pes planus] (acquired)

ICD-10-CM Code:
M21.4
ICD-10 Code for:
Flat foot [pes planus] (acquired)
Is Billable?
Not Valid for Submission
Code Navigator:

Code Classification

  • Diseases of the musculoskeletal system and connective tissue
    (M00–M99)
    • Other joint disorders
      (M20-M25)
      • Other acquired deformities of limbs
        (M21)

M21.4 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of flat foot [pes planus] (acquired). The code is not specific and is NOT valid for the year 2024 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

Specific Coding Applicable to Flat foot [pes planus] (acquired)

Non-specific codes like M21.4 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10-CM codes with a higher level of specificity when coding for flat foot [pes planus] (acquired):

  • Use M21.40 for Flat foot [pes planus] (acquired), unspecified foot - BILLABLE CODE

  • Use M21.41 for Flat foot [pes planus] (acquired), right foot - BILLABLE CODE

  • Use M21.42 for Flat foot [pes planus] (acquired), left foot - BILLABLE CODE

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.


Type 1 Excludes

Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
  • congenital pes planus Q66.5

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Patient Education


Foot Injuries and Disorders

Each of your feet has 26 bones, 33 joints, and more than 100 tendons, muscles, and ligaments. No wonder a lot of things can go wrong. Here are a few common problems:

  • Bunions - hard, painful bumps on the big toe joint
  • Corns and calluses - thickened skin from friction or pressure
  • Plantar warts - warts on the soles of your feet
  • Fallen arches - also called flat feet

Ill-fitting shoes often cause these problems. Aging and being overweight also increase your chances of having foot problems.


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.