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.
Official description
M18Osteoarthritis of first carpometacarpal joint
ICD-10-CM diagnosis code · United States clinical modification
Where M18 sits
- 1
Chapter 13
Diseases of the musculoskeletal system and connective tissue (M00-M99)
- 2
Section
Osteoarthritis (M15-M19)
- 3
Category M18
Osteoarthritis of first carpometacarpal joint
- 4
Code M18
Osteoarthritis of first carpometacarpal joint
Codes under M18
M18 is a non-billable category. Choose the child code that best matches the documented diagnosis.
M18.0Bilateral primary osteoarthritis of first carpometacarpal jointsM18.1Unilateral primary osteoarthritis of first carpometacarpal jointM18.2Bilateral post-traumatic osteoarthritis of first carpometacarpal jointsM18.3Unilateral post-traumatic osteoarthritis of first carpometacarpal jointM18.4Other bilateral secondary osteoarthritis of first carpometacarpal jointsM18.5Other unilateral secondary osteoarthritis of first carpometacarpal jointM18.9Osteoarthritis of first carpometacarpal joint, unspecifiedNotes 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.
Source and release
- Data release
- U.S. ICD-10-CM · FY 2027
- Effective date
- Oct 1, 2026
- Publisher
- Vero Scribe Inc.
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.
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.