ICD-10 · PDGM grouping
M18 Osteoarthritis of first carpometacarpal joint
All 13 codes in the M18 family, with the PDGM clinical group, comorbidity subgroup and primary-position rule CMS assigns, read from the CMS grouper crosswalk v07.2.26 and the CDC FY2027 code file.
Codes in family
13
Can lead a claim
9
Cannot lead a claim
4
What CMS assigns to M18
9 of the 13 codes group to Musculoskeletal Rehabilitation; 4 are assigned no clinical group. None of the 13 is assigned a comorbidity subgroup. 9 of the 13 can lead a claim.
Every code in M18
Descriptions are CDC’s FY2027 wording; where CMS’s grouper abbreviates one, its form is shown beneath.
| Code | Description | Primary position | Clinical group | Comorbidity subgroup |
|---|---|---|---|---|
| M18.0 | Bilateral primary osteoarthritis of first carpometacarpal jointsCMS: Bilateral primary osteoarth of first carpometacarp joints | Can lead a claim | E | None |
| M18.1 Unilateral primary osteoarthritis of first carpometacarpal joint | ||||
| M18.10 | Unilateral primary osteoarthritis of first carpometacarpal joint, unspecified handCMS: Unil prim osteoarth of first carpometacarp joint, unsp hand | Cannot lead a claimPrincipal diagnosis not assigned to a clinical group | None | None |
| M18.11 | Unilateral primary osteoarthritis of first carpometacarpal joint, right handCMS: Unil primary osteoarth of first carpometacarp joint, r hand | Can lead a claim | E | None |
| M18.12 | Unilateral primary osteoarthritis of first carpometacarpal joint, left handCMS: Unil primary osteoarth of first carpometacarp joint, l hand | Can lead a claim | E | None |
| M18.2 | Bilateral post-traumatic osteoarthritis of first carpometacarpal jointsCMS: Bi post-trauma osteoarth of first carpometacarp joints | Can lead a claim | E | None |
| M18.3 Unilateral post-traumatic osteoarthritis of first carpometacarpal joint | ||||
| M18.30 | Unilateral post-traumatic osteoarthritis of first carpometacarpal joint, unspecified handCMS: Unil post-trauma osteoarth of 1st carpometacarp jt,unsp hand | Cannot lead a claimPrincipal diagnosis not assigned to a clinical group | None | None |
| M18.31 | Unilateral post-traumatic osteoarthritis of first carpometacarpal joint, right handCMS: Unil post-trauma osteoarth of 1st carpometacarp jt, r hand | Can lead a claim | E | None |
| M18.32 | Unilateral post-traumatic osteoarthritis of first carpometacarpal joint, left handCMS: Unil post-trauma osteoarth of 1st carpometacarp jt, l hand | Can lead a claim | E | None |
| M18.4 | Other bilateral secondary osteoarthritis of first carpometacarpal jointsCMS: Oth bi secondary osteoarth of first carpometacarp joints | Can lead a claim | E | None |
| M18.5 Other unilateral secondary osteoarthritis of first carpometacarpal joint | ||||
| M18.50 | Other unilateral secondary osteoarthritis of first carpometacarpal joint, unspecified handCMS: Oth unil sec osteoarth of 1st carpometacarp joint, unsp hand | Cannot lead a claimPrincipal diagnosis not assigned to a clinical group | None | None |
| M18.51 | Other unilateral secondary osteoarthritis of first carpometacarpal joint, right handCMS: Oth unil sec osteoarth of first carpometacarp joint, r hand | Can lead a claim | E | None |
| M18.52 | Other unilateral secondary osteoarthritis of first carpometacarpal joint, left handCMS: Oth unil sec osteoarth of first carpometacarp joint, l hand | Can lead a claim | E | None |
| M18.9 | Osteoarthritis of first carpometacarpal joint, unspecified | Cannot lead a claimPrincipal diagnosis not assigned to a clinical group | None | None |
Sources: CMS HH PPS Grouper Software v07.2.26, effective 2026-10-01, for the clinical group, comorbidity subgroup, code-first conventions and primary-position flags; CDC NCHS ICD-10-CM FY2027 code descriptions for the family title and code wording. This is the crosswalk Medicare runs a claim through. Grouping also depends on admission source, timing, the OASIS functional items and the rest of the diagnosis list.
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