M18.5 — Other unilateral secondary osteoarthritis of first carpometacarpal joint
Is M18.5 billable?
No — M18.5 is a non-billable header code. M18.5 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 3 billable codes beneath M18.5.
Billable codes under this header
M18.5 at a glance
| Code | M18.5 |
|---|---|
| Description | Other unilateral secondary osteoarthritis of first carpometacarpal joint |
| Billable | No — header code |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
How is M18.5 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to M18.5. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Osteoarthritis › secondary › hand joint › first carpometacarpal joint
Inclusion terms
Alternative wording in documentation that is classified to M18.5.
- Secondary osteoarthritis of first carpometacarpal joint NOS
Excludes2 — not included here — inherited from Chapter 13
The conditions below are not part of M18.5, but a patient may have both at the same time. When documentation supports it, M18.5 and the excluded code may both be reported.
- 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)
Excludes2 — not included here — inherited from M15-M19
The conditions below are not part of M18.5, but a patient may have both at the same time. When documentation supports it, M18.5 and the excluded code may both be reported.
- osteoarthritis of spine (M47.-)
What codes fall under M18.5? (3)
How long has M18.5 existed?
M18.5 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.
Which conditions are coded to M18.5?
What other codes are in the M18 family? (6)
- M18.0Bilateral primary osteoarthritis of first carpometacarpal joints
- M18.1Unilateral primary osteoarthritis of first carpometacarpal jointnot billable
- M18.2Bilateral post-traumatic osteoarthritis of first carpometacarpal joints
- M18.3Unilateral post-traumatic osteoarthritis of first carpometacarpal jointnot billable
- M18.4Other bilateral secondary osteoarthritis of first carpometacarpal joints
- M18.9Osteoarthritis of first carpometacarpal joint, unspecified