2026 ICD-10-CM Diagnosis Code M02.879Other reactive arthropathies, unspecified ankle and foot

ICD-10-CM Codes›M00–M99›M00-M02›M02

ICD-10-CM M02.879
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M02.879 is a billable ICD-10-CM diagnosis code for other reactive arthropathies, 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 548 through 550. The code is a manifestation code that cannot be reported as the principal diagnosis and flagged as an unspecified code, since codes identifying laterality exist in the same family. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Immune-mediated/reactive arthropathies.

Code Identity

ICD-10-CM Code
M02.879
Billable Status
Yes — Valid for Submission
Code Describes
Other reactive arthropathies, unspecified ankle and foot
Short Description
Other reactive arthropathies, unspecified ankle and foot
Same as the full description in the CMS dataset.
Parent Code
M02.87
Other reactive arthropathies, ankle and foot

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM00-M02Infectious arthropathies
CategoryM02Postinfective and reactive arthropathies
This CodeM02.879Other reactive arthropathies, unspecified ankle and foot

Code EditsBilling

Medicare Code Editor checks that affect claim validity for M02.879.

Manifestation diagnoses
Manifestation codes describe the manifestation of an underlying disease, not the disease itself, and therefore should not be used as a principal diagnosis.
Unspecified codes
Unspecified codes exist in the ICD-10-CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported. The following pages contain the list of unspecified ICD-10-CM diagnosis codes for which there is a more specific code to identify laterality (right, left, bilateral) within that code family.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Arthropathy in Behcet's syndrome of the ankle
  • Arthropathy in Behcet's syndrome of the ankle and/or foot
  • Inflammation of interphalangeal joint of toe
  • Post-infective arthritis of joint of foot
  • Reactive arthritis of first metatarsophalangeal joint
  • Reactive arthritis of interphalangeal joint of toe
  • Reactive arthritis of joint of ankle
  • Reactive arthritis of joint of foot
  • Reactive arthritis of lesser metatarsophalangeal joint
  • Reactive arthritis of subtalar joint
  • Reactive arthritis of talonavicular joint
  • Sexually acquired reactive arthritis
  • Sexually acquired reactive arthritis of joint of ankle
  • Sexually acquired reactive arthritis of joint of foot

Clinical ClassificationClinical

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

CCSR MUS008
Immune-mediated/reactive arthropathies
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Infectious Arthritis

Most kinds of arthritis cause pain and swelling in your joints. Joints are places where two bones meet, such as your elbow or knee. Infectious arthritis is an infection in the joint. The infection comes from a bacterial, viral, or fungal infection that spreads from another part of the body. Symptoms of infectious arthritis include:

Read the full article at MedlinePlus

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

Convert M02.879 to ICD-9-CMHistory

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

ICD-9-CM
711.47 Bact arthritis-ankle
Approximate The match is approximate rather than exact.
ICD-9-CM
711.57 Viral arthritis-ankle
Approximate The match is approximate rather than exact.
ICD-9-CM
711.87 Inf arthritis 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 M02.879Overview

Is M02.879 (Other reactive arthropathies, ankle and foot) a billable code?

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

What MS-DRG does M02.879 group to?

On inpatient claims, other reactive arthropathies, unspecified ankle and foot maps to MS-DRG 548, 549, 550, with relative weights from 0.8741 to 1.9309 depending on complications. Higher weights mean higher Medicare reimbursement.

Can M02.879 be a principal diagnosis?

No. This is a manifestation code: other reactive arthropathies, unspecified ankle and foot describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.

What is the ICD-9 equivalent of M02.879?

Under the General Equivalence Mappings, other reactive arthropathies, unspecified ankle and foot converts to ICD-9-CM 711.47 (bact arthritis-ankle), 711.57 (viral arthritis-ankle), and 711.87 (inf arthritis 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.