2026 ICD-10-CM Diagnosis Code M26.643Arthritis of bilateral temporomandibular joint

ICD-10-CM Codes›M00–M99›M26-M27›M26

ICD-10-CM M26.643
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M26.643 is a billable ICD-10-CM diagnosis code for arthritis of bilateral temporomandibular joint. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 157 through 159. Coders also document this condition as arthritis of left temporomandibular joint. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Any dental condition including traumatic injury, Disorders of jaw, and Nontraumatic dental conditions.

Code Identity

ICD-10-CM Code
M26.643
Billable Status
Yes — Valid for Submission
Code Describes
Arthritis of bilateral temporomandibular joint
Short Description
Arthritis of bilateral temporomandibular joint
Same as the full description in the CMS dataset.
Parent Code
M26.64
Arthritis of temporomandibular joint

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM26-M27Dentofacial anomalies [including malocclusion] and other disorders of jaw
CategoryM26Dentofacial anomalies [including malocclusion]
This CodeM26.643Arthritis of bilateral temporomandibular joint

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Arthritis of left temporomandibular joint
  • Arthritis of right temporomandibular joint
  • Bilateral temporomandibular joint arthritis

Clinical ClassificationClinical

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

CCSR DEN001
Any dental condition including traumatic injury
Default principal diagnosis: inpatient No · outpatient No
CCSR MUS029
Disorders of jaw
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR DEN002
Nontraumatic dental conditions
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Temporomandibular Disorders

Temporomandibular disorders (TMDs) are a group of more than 30 conditions that affect your temporomandibular joints (TMJs). You have two TMJs; one on each side of your jaw. They connect your lower jaw to your skull.

The full article covers:

  • What are temporomandibular disorders (TMDs)?
  • What causes temporomandibular disorders (TMDs)?
  • Who is more likely to develop a temporomandibular disorder (TMD)?
  • What are the symptoms of temporomandibular disorders (TMDs)?
  • How are temporomandibular disorders (TMDs) diagnosed?
  • What are the treatments for temporomandibular disorders (TMDs)?

Read the full article at MedlinePlus

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

Code History & ChangesHistory

Replacement M26.643 replaces the following previously assigned code(s):

  • M26.69 - Other specified disorders of temporomandibular joint
FY 2021AddedAdded to the ICD-10-CM code setEffective October 1, 2020.
FY 2022–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About M26.643Overview

Is M26.643 (Arthritis of temporomandibular joint) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report arthritis of bilateral temporomandibular joint on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M26.643 group to?

When arthritis of bilateral temporomandibular joint is the principal diagnosis on an inpatient stay, it groups to MS-DRG 157, 158, 159, with relative weights from 0.7085 to 1.7168 depending on complications. Higher weights mean higher Medicare reimbursement.

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.