ICD-10 Code M05.42 – Rheumatoid myopathy with rheumatoid arthritis of elbow (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.42 – Rheumatoid myopathy with rheumatoid arthritis of elbow
What it is
This code identifies rheumatoid arthritis affecting the elbow with associated myopathy. It tells you the joint disease and the muscle involvement are both documented.
Clinical signs
Typical findings include elbow pain, swelling, stiffness, and reduced range of motion, along with muscle weakness or wasting near the affected joint. Clinical features vary; refer to documentation.
When to use this code
Use M05.42 when the record clearly documents rheumatoid arthritis of the elbow and rheumatoid myopathy. Apply it when the provider links the muscle disorder to the rheumatoid disease, not to another cause. Check documentation if laterality or joint detail is incomplete.
Do not use for
Do not use this code for rheumatoid arthritis without documented myopathy, or for isolated muscle weakness from another condition. Do not assume elbow involvement unless it is stated.
Coding tip
Verify that both rheumatoid arthritis and myopathy are documented together and that the elbow is specified.