U.S. ICD-10-CM · FY 2027

M18 ICD-10-CM Code: Osteoarthritis of first carpometacarpal joint

A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.

Code definition

Official description

M18

Osteoarthritis of first carpometacarpal joint

ICD-10-CM diagnosis code · United States clinical modification

Classification

Where M18 sits

  1. 1

    Chapter 13

    Diseases of the musculoskeletal system and connective tissue (M00-M99)

  2. 2

    Section

    Osteoarthritis (M15-M19)

  3. 3

    Category M18

    Osteoarthritis of first carpometacarpal joint

  4. 4

    Code M18

    Osteoarthritis of first carpometacarpal joint

More specific choices

Codes under M18

M18 is a non-billable category. Choose the child code that best matches the documented diagnosis.

Documentation details

Notes for this code

Inclusion terms

No inclusion terms are listed for M18.

Code first

No “code first” instruction is listed for M18.

Use additional code

No “use additional code” instruction is listed for M18.

Excludes1

Conditions that should not be reported together with this code.

No Excludes1 note is listed for M18.

Excludes2

Conditions not included here that may be reported separately when present.

No Excludes2 note is listed for M18.

Transparency

Source and release

Data release

U.S. ICD-10-CM · FY 2027

Effective date

Oct 1, 2026

This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.

Review the CDC/NCHS ICD-10-CM source

Code-specific guidance

Frequently asked questions

What does ICD-10-CM code M18 mean?

M18 is the FY 2027 U.S. ICD-10-CM code for “Osteoarthritis of first carpometacarpal joint.”

Is M18 a billable or specific ICD-10-CM code?

No. M18 has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.

Where is M18 located in ICD-10-CM?

M18 is listed in Chapter 13, Diseases of the musculoskeletal system and connective tissue (M00-M99), within Osteoarthritis (M15-M19) (M15–M19), under category M18, Osteoarthritis of first carpometacarpal joint.

What coding notes are listed for M18?

No inclusion terms are listed for M18 in this reference record. No code-first instruction is listed. No Excludes1 note is listed. No Excludes2 note is listed.

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