2026 ICD-10-CM Diagnosis Code M13.879Other specified arthritis, unspecified ankle and foot

ICD-10-CM Codes›M00–M99›M05-M14›M13

ICD-10-CM M13.879
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M13.879 is a billable ICD-10-CM diagnosis code for other specified arthritis, 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 553 through 554. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified joint disorders.

Code Identity

ICD-10-CM Code
M13.879
Billable Status
Yes — Valid for Submission
Code Describes
Other specified arthritis, unspecified ankle and foot
Short Description
Other specified arthritis, unspecified ankle and foot
Same as the full description in the CMS dataset.
Parent Code
M13.87
Other specified arthritis, ankle and foot

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM05-M14Inflammatory polyarthropathies
CategoryM13Other arthritis
This CodeM13.879Other specified arthritis, unspecified ankle and foot

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Allergic arthritis
  • Allergic arthritis of the ankle and/or foot
  • Arthritis of joint of foot
  • Arthritis of joint of toe
  • Arthritis of midtarsal joint
  • Arthropathy associated with a hypersensitivity reaction
  • Calcaneocuboid osteoarthritis secondary to inflammatory arthritis
  • Climacteric arthritis
  • Climacteric arthritis of the ankle and/or foot
  • Inflammation of foot joint
  • Inflammation of interphalangeal joint of toe
  • Inflammation of subtalar joint
  • Osteoarthritis of ankle secondary to inflammatory arthritis
  • Osteoarthritis of calcaneocuboid joint
  • Osteoarthritis of first metatarsophalangeal joint
  • Osteoarthritis of first metatarsophalangeal joint secondary to inflammatory arthritis
  • Osteoarthritis of midfoot
  • Osteoarthritis of midfoot secondary to inflammatory arthritis
  • Osteoarthritis of subtalar joint
  • Osteoarthritis of talonavicular joint
  • Osteoarthritis of toe joint
  • Secondary calcaneocuboid osteoarthritis
  • Secondary osteoarthritis of ankle
  • Secondary osteoarthritis of first metatarsophalangeal joint
  • Secondary osteoarthritis of midfoot
  • Secondary osteoarthritis of subtalar joint
  • Secondary talonavicular osteoarthritis
  • Subtalar osteoarthritis secondary to inflammatory arthritis
  • Talonavicular osteoarthritis secondary to inflammatory arthritis

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

Clinical InformationClinical

  • Allergic Arthritis

    arthritis occurring after the ingestion of allergenic substance(s).

  • Climacteric Arthritis

    arthritis that occurs during menopause.

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 M13.879 to ICD-9-CMHistory

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

ICD-9-CM
716.27 Allerg arthritis-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 M13.879Overview

Is M13.879 (Other specified arthritis, ankle and foot) a billable code?

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

What MS-DRG does M13.879 group to?

When other specified arthritis, unspecified ankle and foot is the principal diagnosis on an inpatient stay, it groups to MS-DRG 553, 554, with relative weights from 0.8301 to 1.2963 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M13.879?

Under the General Equivalence Mappings, other specified arthritis, unspecified ankle and foot converts to ICD-9-CM 716.27 (allerg arthritis-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.