2026 ICD-10-CM Diagnosis Code M66.132Rupture of synovium, left wrist

ICD-10-CM Codes›M00–M99›M65-M67›M66

ICD-10-CM M66.132
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M66.132 is a billable ICD-10-CM diagnosis code for rupture of synovium, left wrist. 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
M66.132
Billable Status
Yes — Valid for Submission
Code Describes
Rupture of synovium, left wrist
Short Description
Rupture of synovium, left wrist
Same as the full description in the CMS dataset.
Parent Code
M66.13
Rupture of synovium, wrist

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM65-M67Disorders of synovium and tendon
CategoryM66Spontaneous rupture of synovium and tendon
This CodeM66.132Rupture of synovium, left wrist

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

Wrist Injuries and Disorders

Your wrist connects your hand to your forearm. It is not one big joint; it has several small joints. This makes it flexible and allows you to move your hand in different ways. The wrist has two big forearm bones and eight small bones known as carpals. It also has tendons and ligaments, which are connective tissues.

The full article covers:

  • What are the types of wrist injuries and disorders?
  • Who is at risk for wrist injuries and disorders?
  • What are the symptoms of wrist injuries and disorders?
  • How are wrist injuries and disorders diagnosed?
  • What are the treatments for wrist injuries and disorders?
  • Can wrist injuries and disorders be prevented?

Read the full article at MedlinePlus

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

Convert M66.132 to ICD-9-CMHistory

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

ICD-9-CM
727.59 Rupture of synovium 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 M66.132Overview

Is M66.132 (Rupture of synovium, wrist) a billable code?

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

What MS-DRG does M66.132 group to?

When rupture of synovium, left wrist 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 M66.132?

Under the General Equivalence Mappings, rupture of synovium, left wrist converts to ICD-9-CM 727.59 (rupture of synovium 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.