2027 ICD-10-CM Diagnosis Code Q66.31Other congenital varus deformities of feet, right foot

ICD-10-CM Codes›Q00-Q99›Q65-Q79›Q66

ICD-10-CM Q66.31
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Q66.31 is a billable ICD-10-CM diagnosis code for other congenital varus deformities of feet, right 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. The code is exempt from POA reporting. Coders also document this condition as bilateral talipes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Musculoskeletal congenital conditions.

Code Identity

ICD-10-CM Code
Q66.31
Billable Status
Yes — Valid for Submission
Code Describes
Other congenital varus deformities of feet, right foot
Short Description
Other congenital varus deformities of feet, right foot
Same as the full description in the CMS dataset.
Parent Code
Q66.3
Other congenital varus 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 CodeQ66.31Other congenital varus deformities of feet, right foot

Present on Admission (POA)Billing

Q66.31 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.

  • Bilateral talipes
  • Congenital bilateral hallux varus
  • Congenital hallux varus
  • Congenital left hallux varus
  • Congenital right hallux varus
  • Congenital varus deformity of foot
  • Talipes varus of bilateral feet
  • Talipes varus of left foot
  • Talipes varus of right foot
  • Varus deformity of great toe

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Q66.31: 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 Q66.31, its category, or a range that includes it.

Excludes1 2

These codes carry an Excludes1 note naming Q66.31: 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

Clinical ClassificationClinical

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

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

Patient EducationClinical

Birth Defects

A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of pregnancy. One out of every 33 babies in the United States is born with a birth defect.

The full article covers:

  • What are birth defects?
  • What causes birth defects?
  • Who is at risk of having a baby with birth defects?
  • How are birth defects diagnosed?
  • What are the treatments for birth defects?
  • Can birth defects be prevented?

Read the full article at MedlinePlus

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

Code History & ChangesHistory

Replacement Q66.31 replaces the following previously assigned code(s):

  • Q66.3 - Other congenital varus deformities of feet
FY 2020AddedAdded to the ICD-10-CM code setEffective October 1, 2019.
FY 2021–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Q66.31Overview

What is the ICD-10 code for other congenital varus deformities of feet, right foot?

The ICD-10-CM code for other congenital varus deformities of feet, right foot is Q66.31 (sometimes written as Q6631). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Q66.31 (Other congenital varus deformities of feet) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other congenital varus deformities of feet, right foot on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Q66.31 group to?

When other congenital varus deformities of feet, right foot is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 566, 565, with relative weights from 0.7374 to 1.4909 depending on complications. Higher weights mean higher Medicare reimbursement.

Is Q66.31 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 other congenital varus deformities of feet, right 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 Q66.31 be reported with a code from Q72?

Not as a rule. The Excludes1 note at Q66, which applies to Q66.31, 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).