Osteoarthritis of first carpometacarpal joint (M18) ICD-10-CM
The M18 code range covers osteoarthritis of first carpometacarpal joint with 17 ICD-10-CM diagnosis codes. 13 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Codes in the M18 Range 17 codes · 13 billable
- M18 Osteoarthritis of first carpometacarpal jointNon-billable
- M18.0 Bilateral primary osteoarthritis of first carpometacarpal joints
- M18.1 Unilateral primary osteoarthritis of first carpometacarpal jointNon-billable
- M18.10 Unilateral primary osteoarthritis of first carpometacarpal joint, unspecified hand
- M18.11 Unilateral primary osteoarthritis of first carpometacarpal joint, right hand
- M18.12 Unilateral primary osteoarthritis of first carpometacarpal joint, left hand
- M18.2 Bilateral post-traumatic osteoarthritis of first carpometacarpal joints
- M18.3 Unilateral post-traumatic osteoarthritis of first carpometacarpal jointNon-billable
- M18.30 Unilateral post-traumatic osteoarthritis of first carpometacarpal joint, unspecified hand
- M18.31 Unilateral post-traumatic osteoarthritis of first carpometacarpal joint, right hand
- M18.32 Unilateral post-traumatic osteoarthritis of first carpometacarpal joint, left hand
- M18.4 Other bilateral secondary osteoarthritis of first carpometacarpal joints
- M18.5 Other unilateral secondary osteoarthritis of first carpometacarpal jointNon-billable
- M18.50 Other unilateral secondary osteoarthritis of first carpometacarpal joint, unspecified hand
- M18.51 Other unilateral secondary osteoarthritis of first carpometacarpal joint, right hand
- M18.52 Other unilateral secondary osteoarthritis of first carpometacarpal joint, left hand
- M18.9 Osteoarthritis of first carpometacarpal joint, unspecified
About the M18 Code Range
Osteoarthritis in this category affects the first carpometacarpal joint of the thumb.
The subdivisions separate primary, post-traumatic, and other secondary osteoarthritis. Each group distinguishes both hands from one hand. Primary osteoarthritis appears under M18.0 and M18.1; post-traumatic osteoarthritis appears under M18.2 and M18.3. Other secondary osteoarthritis follows the same pattern under M18.4 and M18.5. Codes for one hand further distinguish right, left, or unspecified hand. M18.9 identifies osteoarthritis of this joint without further specification.
Questions About This Page
How many billable codes are in the M18 range?
Of the 17 codes in this range, 13 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the M18 range classify?
The range classifies osteoarthritis of first carpometacarpal joint. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
