2027 ICD-10-CM Diagnosis Code Q66.80Congenital vertical talus deformity, unspecified foot

ICD-10-CM Codes›Q00-Q99›Q65-Q79›Q66

ICD-10-CM Q66.80
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Q66.80 is a billable ICD-10-CM diagnosis code for congenital vertical talus deformity, unspecified foot. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 564 through 566, 795. The code is exempt from POA reporting. Coders also document this condition as congenital atresia of external auditory canal. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Musculoskeletal congenital conditions.

Code Identity

ICD-10-CM Code
Q66.80
Billable Status
Yes — Valid for Submission
Code Describes
Congenital vertical talus deformity, unspecified foot
Short Description
Congenital vertical talus deformity, unspecified foot
Same as the full description in the CMS dataset.
Parent Code
Q66.8
Other congenital deformities of feet

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ65-Q79Congenital malformations and deformations of the musculoskeletal system
CategoryQ66Congenital deformities of feet
This CodeQ66.80Congenital vertical talus deformity, unspecified foot

Present on Admission (POA)Billing

Q66.80 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Congenital malformations and deformations of the musculoskeletal system (Q65-Q79).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Congenital atresia of external auditory canal
  • Congenital atresia of external ear
  • Congenital vertical talus
  • External auditory canal atresia, vertical talus, hypertelorism syndrome
  • Hypertelorism
  • Persistent dislocation of joint
  • Rigid flat foot

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Q66.80: its own notes plus those printed at Q66 and Chapter 17. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Q66 Congenital deformities of feet applies to 32 codes
  • reduction defects of feet (Q72.-)
  • valgus deformities (acquired) (M21.0-)
  • varus deformities (acquired) (M21.1-)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • inborn errors of metabolism (E70-E88)

Notes

General instructions on how these codes are used.

From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • Codes from this chapter are not for use on maternal records

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name Q66.80, its category, or a range that includes it.

Excludes1 2

These codes carry an Excludes1 note naming Q66.80: they are not reported together with it, unless the two conditions are unrelated.

  • M20 Acquired deformities of fingers and toes
    congenital deformities and malformations of fingers and toes (Q66.-, Q68-Q70, Q74.-) names Q66.-, which includes this code
  • M21 Other acquired deformities of limbs
    congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74) names Q65-Q66, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MAL008
Musculoskeletal congenital conditions
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Vertical Talus

    congenital severe form of flatfoot involving dislocation of the navicular bone of foot on the talus.

Patient EducationClinical

Ankle Injuries and Disorders

Your ankle bone and the ends of your two lower leg bones make up the ankle joint. Your ligaments, which connect bones to one another, stabilize and support it. Your muscles and tendons move it.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Q66.80 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
754.61 Congenital pes planus
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Q66.80Overview

What is the ICD-10 code for congenital vertical talus deformity, unspecified foot?

The ICD-10-CM code for congenital vertical talus deformity, unspecified foot is Q66.80 (sometimes written as Q6680). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Q66.80 (Other congenital deformities of feet) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report congenital vertical talus deformity, unspecified foot on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Q66.80 group to?

When congenital vertical talus deformity, unspecified foot is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 795, 566, 565, with relative weights from 0.2022 to 1.4909 depending on complications. Higher weights mean higher Medicare reimbursement.

Is Q66.80 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for congenital vertical talus deformity, unspecified foot on inpatient claims. The code appears in the Congenital malformations and deformations of the musculoskeletal system (Q65-Q79) range of the CMS exempt list.

Can Q66.80 be reported with a code from Q72?

Not as a rule. The Excludes1 note at Q66, which applies to Q66.80, lists "reduction defects of feet (Q72.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).