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Q66 ICD-10-CM Code: Congenital deformities of feet

ICD-10-CM Code View

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FY 2026 Apr update / Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0) / Congenital malformations and deformations of the musculoskeletal system (Q65-Q79)

Q66

Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidance

Congenital deformities of feet

Congenital deformities of feet

CMS-HCC V28

N/A

Not mapped

CMS-HCC V24

N/A

Not mapped

ACA/HHS

N/A

Not mapped

ESRD/PACE

N/A

Not mapped

RXHCC

N/A

Not mapped

Code Book Path

Official
Q6Congenital malformations and deformations of the musculoskeletal system (Q65-Q79)
Q66Congenital deformities of feet

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for Q66 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for Q66 in this effective period.

Related Child Codes

Official
Q66.0Congenital talipes equinovarus
Q66.1Congenital talipes calcaneovarus
Q66.2Congenital metatarsus (primus) varus
Q66.3Other congenital varus deformities of feet
Q66.4Congenital talipes calcaneovalgus

Includes

Official

ICD-10-CM does not list Includes notes for Q66 in this effective period.

Excludes 1

Official
  • reduction defects of feet (Q72.-)
  • valgus deformities (acquired) (M21.0-)
  • varus deformities (acquired) (M21.1-)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for Q66 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for Q66 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for Q66 in this effective period.

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Coder workflow notes

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What This Code Means

Q66 is the ICD-10-CM diagnosis code for congenital deformities of feet. Q66 sits in the ICD-10-CM chapter for congenital malformations, deformations and chromosomal abnormalities (q00-qa0), within the section covering congenital malformations and deformations of the musculoskeletal system (q65-q79).

Header codes like Q66 cannot be reported on claims directly, they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at Q66's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q66 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Excludes 1, Do NOT code together

  • reduction defects of feet (Q72.-)
  • valgus deformities (acquired) (M21.0-)
  • varus deformities (acquired) (M21.1-)

Child Codes

Code Hierarchy

Q66Congenital deformities of feet
Q66Congenital deformities of feet

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