All ICD10 Codes

M21.4

Non-Billable
ChapterM00–M99
Ranksubcategory
Official Description

Flat foot [pes planus] (acquired)

Use a more specific code (3 billable)
M21.40Flat foot [pes planus] (acquired), unspecified footM21.41Flat foot [pes planus] (acquired), right footM21.42Flat foot [pes planus] (acquired), left foot
Metadata & Insights
  • •Non-billable category (requires more specific sub-code).
  • •Chapter 13: Diseases of the Musculoskeletal System and Connective Tissue (M00-M99).

Instructional Notes

Excludes1(Not coded here. Use a different code.)
  • congenital pes planus (Q66.5-)
General instructions are available for the parent sections:
View CH13 NotesView M20-M25 NotesView M21 Notes

Clinical Hierarchy

BillableHas subcodes
CH13Diseases of the musculoskeletal system and connective tissue (M00-M99)
M20-M25Other joint disorders (M20-M25)
M21Other acquired deformities of limbs
M21.4Flat foot [pes planus] (acquired)Not billable
M21.40Flat foot [pes planus] (acquired), unspecified footBillable
M21.41Flat foot [pes planus] (acquired), right footBillable
M21.42Flat foot [pes planus] (acquired), left footBillable

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to M21.4:

categoryM21
Other acquired deformities of limbs
View context instructions
blockM20-M25
Other joint disorders (M20-M25)
View context instructions
chapterCH13
Diseases of the musculoskeletal system and connective tissue (M00-M99)
View context instructions

MS-DRG Classification

2026

No direct MS-DRG triggers identified.

Cross Reference

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