ICD-10 Code M05.461 – Rheumatoid myopathy with rheumatoid arthritis of right knee (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.461 – Rheumatoid myopathy with rheumatoid arthritis of right knee
What it is
This code identifies rheumatoid arthritis affecting the right knee with associated rheumatoid myopathy. It indicates inflammatory joint disease plus muscle involvement documented by the clinician.
Clinical signs
Typical findings include pain, swelling, stiffness, and reduced motion in the right knee, with weakness or other muscle symptoms linked to rheumatoid disease. Clinical features vary; refer to documentation.
When to use this code
Use M05.461 when the record specifically documents rheumatoid arthritis of the right knee and rheumatoid myopathy together. You should code it when the provider links the muscle disorder to rheumatoid disease, not when only joint symptoms are noted.
Do not use for
Do not use this code for rheumatoid arthritis without documented myopathy, or for myopathy not related to rheumatoid disease. Check documentation if the affected knee is not clearly the right side.
Coding tip
Verify both the rheumatoid myopathy and the right-knee involvement are explicitly documented before assigning M05.461.