2026 ICD-10-CM Diagnosis Code M67.231Synovial hypertrophy, not elsewhere classified, right forearm

ICD-10-CM Codes›M00–M99›M65-M67›M67

ICD-10-CM M67.231
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M67.231 is a billable ICD-10-CM diagnosis code for synovial hypertrophy, not elsewhere classified, right forearm. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Tendon and synovial disorders.

Code Identity

ICD-10-CM Code
M67.231
Billable Status
Yes — Valid for Submission
Code Describes
Synovial hypertrophy, not elsewhere classified, right forearm
Short Description
Synovial hypertrophy, NEC, right forearm
Parent Code
M67.23
Synovial hypertrophy, not elsewhere classified, forearm

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM65-M67Disorders of synovium and tendon
CategoryM67Other disorders of synovium and tendon
This CodeM67.231Synovial hypertrophy, not elsewhere classified, right forearm

Clinical ClassificationClinical

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

CCSR MUS009
Tendon and synovial disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Arm Injuries and Disorders

Of the 206 bones in your body, three of them are in your arm: the humerus, radius, and ulna. Your arms are also made up of muscles, joints, tendons, and other connective tissue. Injuries to any of these parts of the arm can occur during sports, a fall, or an accident.

Read the full article at MedlinePlus

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

Convert M67.231 to ICD-9-CMHistory

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

ICD-9-CM
727.89 Synov/tend/bursa dis NEC
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 M67.231Overview

Is M67.231 (Synovial hypertrophy, not elsewhere classified, forearm) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report synovial hypertrophy, not elsewhere classified, right forearm on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M67.231 group to?

When synovial hypertrophy, not elsewhere classified, right forearm 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 M67.231?

Under the General Equivalence Mappings, synovial hypertrophy, not elsewhere classified, right forearm converts to ICD-9-CM 727.89 (synov/tend/bursa dis NEC). 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.