2027 ICD-10-CM Diagnosis Code M12.9Arthropathy, unspecified

ICD-10-CM Codes›M00–M99›M05-M14›M12

ICD-10-CM M12.9
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

M12.9 is a billable ICD-10-CM diagnosis code for arthropathy, unspecified. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) 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
M12.9
Billable Status
Yes — Valid for Submission
Code Describes
Arthropathy, unspecified
Short Description
Arthropathy, unspecified
Same as the full description in the CMS dataset.
Parent Code
M12
Other and unspecified arthropathy

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM05-M14Inflammatory polyarthropathies
CategoryM12Other and unspecified arthropathy
This CodeM12.9Arthropathy, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute arthropathy
  • Arthropathy
  • Arthropathy associated with cystic fibrosis
  • Arthropathy associated with syringomyelia
  • Arthropathy of elbow
  • Arthropathy of joint of hand
  • Arthropathy of knee joint
  • Arthropathy of pelvis
  • Arthropathy of right elbow
  • Chronic arthropathy
  • Human leukocyte antigen B27 negative arthropathy
  • Inflammation of ankle joint
  • Subacute arthropathy

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to M12.9: its own notes plus those printed at M12, block M00-M25, and Chapter 13. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Block M00-M25 applies to 2,249 codes
  • Disorders affecting predominantly peripheral (limb) joints

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From M12 Other and unspecified arthropathy applies to 169 codes

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • arthropathic psoriasis (L40.5-)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • compartment syndrome (traumatic) (T79.A-)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Notes

General instructions on how these codes are used.

From Chapter 13 (M00-M99) Diseases of the musculoskeletal system and connective tissue applies to 6,687 codes
  • Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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

Clinical InformationClinical

  • Joint Diseases

    diseases involving the joints.

Patient EducationClinical

Joint Disorders

Your joints are places where two or more bones come together. Your shoulders, elbows, hips, knees, and knuckles are all joints. Your spine has joints, too.

The full article covers:

  • What are joints?
  • What are joint disorders?
  • What diseases can affect the joints?
  • What types of joint disorders happen from sudden injuries?
  • What types of joint disorders happen from overuse?
  • How can I keep my joints healthy?

Read the full article at MedlinePlus

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

Convert M12.9 to ICD-9-CMHistory

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

ICD-9-CM
716.90 Arthropathy NOS-unspec
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About M12.9Overview

What is the ICD-10 code for arthropathy, unspecified?

The ICD-10-CM code for arthropathy, unspecified is M12.9 (sometimes written as M129). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is M12.9 (Other and unspecified arthropathy) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report arthropathy, unspecified on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does M12.9 group to?

When arthropathy, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 554, 553, with relative weights from 0.8328 to 1.2492 depending on complications. Higher weights mean higher Medicare reimbursement.

Can M12.9 be reported with J38.7?

Not as a rule. The Excludes1 note at M12, which applies to M12.9, lists "cricoarytenoid arthropathy (J38.7)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What is the ICD-9 equivalent of M12.9?

Under the General Equivalence Mappings, arthropathy, unspecified converts to ICD-9-CM 716.90 (arthropathy NOS-unspec). The mapping is approximate, so confirm the match fits the documentation.