2026 ICD-10-CM Diagnosis Code M67.379Transient synovitis, unspecified ankle and foot

ICD-10-CM Codes›M00–M99›M65-M67›M67

ICD-10-CM M67.379
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M67.379 is a billable ICD-10-CM diagnosis code for transient synovitis, unspecified ankle and foot. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 557 through 558. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Tendon and synovial disorders.

Code Identity

ICD-10-CM Code
M67.379
Billable Status
Yes — Valid for Submission
Code Describes
Transient synovitis, unspecified ankle and foot
Short Description
Transient synovitis, unspecified ankle and foot
Same as the full description in the CMS dataset.
Parent Code
M67.37
Transient synovitis, ankle and foot

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM65-M67Disorders of synovium and tendon
CategoryM67Other disorders of synovium and tendon
This CodeM67.379Transient synovitis, unspecified ankle and foot

Clinical ClassificationClinical

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

CCSR MUS009
Tendon and synovial 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 M67.379 to ICD-9-CMHistory

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

ICD-9-CM
727.09 Synovitis NEC
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 M67.379Overview

Is M67.379 (Transient synovitis, ankle and foot) a billable code?

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

What MS-DRG does M67.379 group to?

When transient synovitis, unspecified ankle and foot is the principal diagnosis on an inpatient stay, it groups to MS-DRG 557, 558, with relative weights from 0.8932 to 1.4869 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M67.379?

Under the General Equivalence Mappings, transient synovitis, unspecified ankle and foot converts to ICD-9-CM 727.09 (synovitis NEC). 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.