2026 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 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

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 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 564 through 566. 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 other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

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

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Deformity
      • vertical talus (congenital)
    • Vertical talus(congenital)

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

  • Hypertelorism

    abnormal increase in the interorbital distance due to overdevelopment of the lesser wings of the sphenoid.

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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Q66.80Overview

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, 2025 through September 30, 2026.

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, 565, 566, with relative weights from 0.7493 to 1.5436 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.

What is the ICD-9 equivalent of Q66.80?

Under the General Equivalence Mappings, congenital vertical talus deformity, unspecified foot converts to ICD-9-CM 754.61 (congenital pes planus). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.