2026 ICD-10-CM Diagnosis Code M20.031Swan-neck deformity of right finger(s)

ICD-10-CM Codes›M00–M99›M20-M25›M20

ICD-10-CM M20.031
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M20.031 is a billable ICD-10-CM diagnosis code for swan-neck deformity of right finger(s). 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acquired deformities (excluding foot).

Code Identity

ICD-10-CM Code
M20.031
Billable Status
Yes — Valid for Submission
Code Describes
Swan-neck deformity of right finger(s)
Short Description
Swan-neck deformity of right finger(s)
Same as the full description in the CMS dataset.
Parent Code
M20.03
Swan-neck deformity

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM20-M25Other joint disorders
CategoryM20Acquired deformities of fingers and toes
This CodeM20.031Swan-neck deformity of right finger(s)

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Extension deformity of finger
  • Flexion deformity of finger of bilateral hands
  • Flexion deformity of finger of left hand
  • Flexion deformity of finger of right hand
  • Swan-neck deformity
  • Swan-neck deformity of finger of bilateral hands
  • Swan-neck deformity of finger of left hand
  • Swan-neck deformity of finger of right hand

Clinical ClassificationClinical

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

CCSR MUS023
Acquired deformities (excluding foot)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Finger Injuries and Disorders

You use your fingers and thumbs to do everything from grasping objects to playing musical instruments to typing. When there is something wrong with them, it can make life difficult. Common problems include:

Read the full article at MedlinePlus

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

Convert M20.031 to ICD-9-CMHistory

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

ICD-9-CM
736.22 Swan-neck deformity
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 M20.031Overview

Is M20.031 (Swan-neck deformity) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report swan-neck deformity of right finger(s) on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M20.031 group to?

When swan-neck deformity of right finger(s) 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.

What is the ICD-9 equivalent of M20.031?

Under the General Equivalence Mappings, swan-neck deformity of right finger(s) converts to ICD-9-CM 736.22 (swan-neck deformity). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.