2026 ICD-10-CM Diagnosis Code M77.42Metatarsalgia, left foot

ICD-10-CM Codes›M00–M99›M70-M79›M77

ICD-10-CM M77.42
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M77.42 is a billable ICD-10-CM diagnosis code for metatarsalgia, left 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 bilateral metatarsalgia. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified connective tissue disease.

Code Identity

ICD-10-CM Code
M77.42
Billable Status
Yes — Valid for Submission
Code Describes
Metatarsalgia, left foot
Short Description
Metatarsalgia, left foot
Same as the full description in the CMS dataset.
Parent Code
M77.4
Metatarsalgia

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM70-M79Other soft tissue disorders
CategoryM77Other enthesopathies
This CodeM77.42Metatarsalgia, left foot

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral metatarsalgia
  • Metatarsalgia
  • Metatarsalgia of left foot
  • Metatarsalgia of right foot
  • Pain in bilateral feet

Clinical ClassificationClinical

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

CCSR MUS025
Other specified connective tissue disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Metatarsalgia

    pain in the region of the metatarsus. it can include pain in the metatarsal bones; metatarsophalangeal joint; and/or intermetatarsal joints (tarsal joints).

  • Morton Neuroma

    a nerve inflammation in the foot caused by chronic compression of the plantar nerve between the metatarsal bones.

  • Metatarsal Bones

    the five long bones of the metatarsus, articulating with the tarsal bones proximally and the phalanges of toes distally.

Patient EducationClinical

Foot Injuries and Disorders

Each of your feet has 26 bones, 33 joints, and more than 100 tendons, muscles, and ligaments. No wonder a lot of things can go wrong. Here are a few common problems:

Read the full article at MedlinePlus

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

Convert M77.42 to ICD-9-CMHistory

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

ICD-9-CM
726.70 Ankle enthesopathy 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 M77.42Overview

Is M77.42 (Metatarsalgia) a billable code?

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

What MS-DRG does M77.42 group to?

When metatarsalgia, left 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 M77.42?

Under the General Equivalence Mappings, metatarsalgia, left foot converts to ICD-9-CM 726.70 (ankle enthesopathy 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.