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ICD-10-CM 2027 diagnosis code

M21.06Valgus deformity, not elsewhere classified, knee

Not billable — use a more specific code

M21.06 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it.

Looking up by condition? See ICD-10 code for Knock knee, ICD-10 code for Valgum genu.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About M21.06

M21.06 is the ICD-10-CM diagnosis code for valgus deformity, not elsewhere classified, knee. It belongs to category M21 (other acquired deformities of limbs), block M20-M25 (other joint disorders) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within M21.0 (valgus deformity, not elsewhere classified), M21.06 is specifically for valgus deformity, not elsewhere classified, knee. Related codes cover unspecified site (M21.00), elbow (M21.02), hip (M21.05) and ankle (M21.07).

To report this condition, pick the subcode that matches the documentation: M21.061 (knee), M21.062 (knee) and M21.069 (knee).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under M21.06

Coding notes

Applicable toConditions and synonyms classified to this code
  • Genu valgum
  • Knock knee

Notes that apply from higher levels

Instructions written at a parent level also apply to M21.06.

› From M21.0 Valgus deformity, not elsewhere classified
Excludes1
  • metatarsus valgus (Q66.6)
  • talipes calcaneovalgus (Q66.4-)
› From M21 Other acquired deformities of limbs
Excludes1
  • acquired absence of limb (Z89.-)
  • congenital absence of limbs (Q71-Q73)
  • congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74)
Excludes2
  • acquired deformities of fingers or toes (M20.-)
  • coxa plana (M91.2)

Broader instructions also apply from M20-M25 Other joint disorders and Chapter 13: Diseases of the musculoskeletal system and connective tissue.

Alphabetic index entries

3 entries

Terms in the official ICD-10-CM index that lead to M21.06.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about M21.06

Is M21.06 billable?

No. M21.06 is a header code. Report one of its more specific subcodes instead.