2026 ICD-10-CM Diagnosis Code M67.979Unspecified disorder of synovium and tendon, unspecified ankle and foot

ICD-10-CM Codes›M00–M99›M65-M67›M67

ICD-10-CM M67.979
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M67.979 is a billable ICD-10-CM diagnosis code for unspecified disorder of synovium and tendon, 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. Coders also document this condition as disorder of flexor hallucis longus tendon. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Tendon and synovial disorders.

Code Identity

ICD-10-CM Code
M67.979
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified disorder of synovium and tendon, unspecified ankle and foot
Short Description
Unsp disorder of synovium and tendon, unsp ankle and foot
Parent Code
M67.97
Unspecified disorder of synovium and tendon, 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 CodeM67.979Unspecified disorder of synovium and tendon, unspecified ankle and foot

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Disorder of flexor hallucis longus tendon
  • Disorder of tendon of ankle region
  • Disorder of tendon of foot
  • Tendinosis of ankle region
  • Tendinosis of 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 M67.979 to ICD-9-CMHistory

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

ICD-9-CM
727.9 Synov/tend/bursa dis NOS
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 M67.979Overview

Is M67.979 (Unspecified disorder of synovium and tendon, ankle and foot) a billable code?

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

What MS-DRG does M67.979 group to?

When unspecified disorder of synovium and tendon, 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 M67.979?

Under the General Equivalence Mappings, unspecified disorder of synovium and tendon, unspecified ankle and foot converts to ICD-9-CM 727.9 (synov/tend/bursa dis NOS). 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.