M18.1
Header — not billableUnilateral primary osteoarthritis of first carpometacarpal joint
The ICD-10 code for unilateral primary osteoarthritis of first carpometacarpal joint is M18.1.
M18.1 is a non-billable header code. It groups related conditions but cannot be used on its own for reimbursement — select one of the 3 more specific codes below.
Clinical notes
Also known as
Alternate wording, synonyms, or specific conditions that fall under this code, listed to help confirm you've picked the right one.
- Primary osteoarthritis of first carpometacarpal joint NOS
Documentation support
General coding-documentation guidance — not a substitute for payer-specific requirements or professional coding judgment.
- •This is a non-billable header code. Documentation must support a more specific child code before this diagnosis can be reported on a claim.
- •Laterality-specific codes exist for this condition — confirm the affected side is documented.
- •As a general rule, code to the highest level of specificity supported by the documentation in the medical record.
Related codes in this category
- M18.0Bilateral primary osteoarthritis of first carpometacarpal joints
- M18.2Bilateral post-traumatic osteoarthritis of first carpometacarpal joints
- M18.3Unilateral post-traumatic osteoarthritis of first carpometacarpal jointnon-billable header
- M18.4Other bilateral secondary osteoarthritis of first carpometacarpal joints
- M18.5Other unilateral secondary osteoarthritis of first carpometacarpal jointnon-billable header
- M18.9Osteoarthritis of first carpometacarpal joint, unspecified
- M18.1Unilateral primary osteoarthritis of first carpometacarpal jointnon-billable header