ICD-10 Code M05.439 – Rheumatoid myopathy with rheumatoid arthritis of unspecified wrist (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.439 – Rheumatoid myopathy with rheumatoid arthritis of unspecified wrist
What it is
This code identifies rheumatoid arthritis affecting an unspecified wrist, with associated rheumatoid myopathy. It signals joint inflammation plus muscle involvement linked to rheumatoid disease.
Clinical signs
Expect wrist pain, swelling, stiffness, and reduced range of motion, along with muscle weakness or wasting related to rheumatoid myopathy. Clinical features vary; refer to documentation.
When to use this code
Use this code when the record documents rheumatoid arthritis in an unspecified wrist and also states rheumatoid myopathy. It applies when the provider links the muscle disorder to the rheumatoid condition. If laterality is not documented, you should not assume it.
Do not use for
Do not use this code for wrist arthritis without documented rheumatoid myopathy, or for myopathy caused by another disorder. Check documentation if the wrist side is specified or if the diagnosis is uncertain.
Coding tip
Verify that both the rheumatoid arthritis and the myopathy are explicitly documented before assigning M05.439.