2027 ICD-10-CM Diagnosis Code M18.11Unilateral primary osteoarthritis of first carpometacarpal joint, right hand

ICD-10-CM Codes›M00–M99›M15-M19›M18

ICD-10-CM M18.11
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

M18.11 is a billable ICD-10-CM diagnosis code for unilateral primary osteoarthritis of first carpometacarpal joint, right hand. 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. Coders also document this condition as degenerative joint disease of thumb. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Osteoarthritis.

Code Identity

ICD-10-CM Code
M18.11
Billable Status
Yes — Valid for Submission
Code Describes
Unilateral primary osteoarthritis of first carpometacarpal joint, right hand
Short Description
Unil primary osteoarth of first carpometacarp joint, r hand
Parent Code
M18.1
Unilateral primary osteoarthritis of first carpometacarpal joint

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM15-M19Osteoarthritis
CategoryM18Osteoarthritis of first carpometacarpal joint
This CodeM18.11Unilateral primary osteoarthritis of first carpometacarpal joint, right hand

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Degenerative joint disease of thumb
  • Osteoarthritis of first carpometacarpal joint of right hand

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to M18.11: its own notes plus those printed at block M00-M25, block M15-M19, 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

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 Block M15-M19 Osteoarthritis applies to 98 codes
  • osteoarthritis of spine (M47.-)
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.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name M18.11, its category, or a range that includes it.

Excludes1 5

These codes carry an Excludes1 note naming M18.11: they are not reported together with it, unless the two conditions are unrelated.

  • M12 Other and unspecified arthropathy
    arthrosis (M15-M19) names M15-M19, which includes this code
  • M13 Other arthritis
    arthrosis (M15-M19) names M15-M19, which includes this code
  • M13 Other arthritis
    osteoarthritis (M15-M19) names M15-M19, which includes this code
  • M13.8 Other specified arthritis
    osteoarthritis (M15-M19) names M15-M19, which includes this code
  • M15 Polyosteoarthritis
    bilateral involvement of single joint (M16-M19) names M16-M19, which includes this code

Excludes2 1

These codes carry an Excludes2 note naming M18.11: its condition is not part of those codes, and both may be reported when the patient has both.

  • M19.04 Primary osteoarthritis, hand
    primary osteoarthritis of first carpometacarpal joint (M18.0-, M18.1-) names M18.1-, which includes this code

Clinical ClassificationClinical

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

CCSR MUS006
Osteoarthritis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Osteoarthritis

Osteoarthritis, sometimes called OA, is a type of arthritis that only affects the joints, usually in the hands, knees, hips, neck, and lower back. It's the most common type of arthritis.

The full article covers:

  • What is osteoarthritis?
  • What are the symptoms of osteoarthritis?
  • What causes osteoarthritis?
  • Who is more likely to develop osteoarthritis?
  • How is osteoarthritis diagnosed?
  • What are the treatments for osteoarthritis?

Read the full article at MedlinePlus

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

Convert M18.11 to ICD-9-CMHistory

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

ICD-9-CM
715.14 Loc prim osteoarth-hand
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 M18.11Overview

Is M18.11 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unilateral primary osteoarthritis of first carpometacarpal joint, right hand on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does M18.11 group to?

When unilateral primary osteoarthritis of first carpometacarpal joint, right hand 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.

What is the ICD-9 equivalent of M18.11?

Under the General Equivalence Mappings, unilateral primary osteoarthritis of first carpometacarpal joint, right hand converts to ICD-9-CM 715.14 (loc prim osteoarth-hand). The mapping is approximate, so confirm the match fits the documentation.