2026 ICD-10-CM Diagnosis Code M25.373Other instability, unspecified ankle

ICD-10-CM Codes›M00–M99›M20-M25›M25

ICD-10-CM M25.373
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M25.373 is a billable ICD-10-CM diagnosis code for other instability, unspecified ankle. 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 Other specified joint disorders.

Code Identity

ICD-10-CM Code
M25.373
Billable Status
Yes — Valid for Submission
Code Describes
Other instability, unspecified ankle
Short Description
Other instability, unspecified ankle
Same as the full description in the CMS dataset.
Parent Code
M25.37
Other instability, ankle and foot

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM20-M25Other joint disorders
CategoryM25Other joint disorder, not elsewhere classified
This CodeM25.373Other instability, unspecified ankle

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute ankle instability
  • Ankle instability
  • Ankle joint hypermobility
  • Ankle joint laxity
  • Chronic ankle instability
  • Chronic instability of ankle syndesmosis
  • Chronic instability of joint
  • Finding of active range of ankle dorsiflexion
  • Finding of active range of ankle plantar flexion
  • Finding of passive range of ankle dorsiflexion
  • Finding of passive range of ankle plantar flexion
  • Finding of range of ankle plantar flexion
  • Global instability of ankle
  • Increased active range of ankle dorsiflexion
  • Increased active range of ankle plantar flexion
  • Increased passive range of ankle dorsiflexion
  • Increased passive range of ankle plantar flexion
  • Increased range of ankle movement

Clinical ClassificationClinical

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

CCSR MUS007
Other specified joint disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

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 M25.373 to ICD-9-CMHistory

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

ICD-9-CM
718.87 Jt derangement NEC-ankle
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 M25.373Overview

Is M25.373 (Other instability, ankle and foot) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other instability, unspecified ankle on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M25.373 group to?

When other instability, unspecified ankle 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 M25.373?

Under the General Equivalence Mappings, other instability, unspecified ankle converts to ICD-9-CM 718.87 (jt derangement NEC-ankle). 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.