M21.4 is the ICD-10 code for Flat foot [pes planus] (acquired). It is a four-character subcategory of M21 (Other acquired deformities of limbs), the most specific level in the WHO edition. It belongs to the block M20–M25 (Other joint disorders) in Chapter XIII, Diseases of the musculoskeletal system and connective tissue.
- Code type
- Subcategory (4 characters)
- Chapter
- XIII · M00–M99
- Classification
- WHO ICD-10, 2019 version
What M21.4 excludes
Conditions that look similar but belong under another code.
- congenital pes planus Q66.5
M21.4 in national editions
Countries report with their own edition of ICD-10. Most keep the WHO code and add more specific codes beneath it.
M21.4Ervervet plattfot
DM214Erhvervet platfod
M21.4Hankinnainen lattajalka
M21.4Plattfuß [Pes planus] (erworben)
M21.4Pied plat [pes planus] (acquis)
M21.4platvoet [pes planus] (verworven)
Listed through more specific codes:
- M21.40Flat foot [pes planus] (acquired), unspecified foot
- M21.41Flat foot [pes planus] (acquired), right foot
- M21.42Flat foot [pes planus] (acquired), left foot
Based on the World Health Organization’s International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10), 2019 version, and the national editions published by each country’s health authority. This page is a reference, not coding advice; follow your national coding rules when you report.
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