2026 ICD-10-CM Diagnosis Code M24.671Ankylosis, right ankle

ICD-10-CM Codes›M00–M99›M20-M25›M24

ICD-10-CM M24.671
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M24.671 is a billable ICD-10-CM diagnosis code for ankylosis, right ankle. 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
M24.671
Billable Status
Yes — Valid for Submission
Code Describes
Ankylosis, right ankle
Short Description
Ankylosis, right ankle
Same as the full description in the CMS dataset.
Parent Code
M24.67
Ankylosis, ankle and foot

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM20-M25Other joint disorders
CategoryM24Other specific joint derangements
This CodeM24.671Ankylosis, right ankle

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Ankle joint ankylosis
  • Ankylosis of joint of left ankle
  • Ankylosis of joint of right ankle
  • Arthrofibrosis of joint of ankle
  • Arthrofibrosis of joint of left ankle region
  • Arthrofibrosis of joint of right ankle region
  • Bilateral ankylosis of joint of ankles
  • Bilateral arthrofibrosis of joint of ankle regions

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

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 M24.671 to ICD-9-CMHistory

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

ICD-9-CM
718.57 Ankylosis-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 M24.671Overview

Is M24.671 (Ankylosis, ankle and foot) a billable code?

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

What MS-DRG does M24.671 group to?

When ankylosis, right ankle 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 M24.671?

Under the General Equivalence Mappings, ankylosis, right ankle converts to ICD-9-CM 718.57 (ankylosis-ankle). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.