ICD-10 Code M05.459 – Rheumatoid myopathy with rheumatoid arthritis of unspecified hip (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.459 – Rheumatoid myopathy with rheumatoid arthritis of unspecified hip
What it is
This code identifies rheumatoid arthritis affecting an unspecified hip, with associated rheumatoid myopathy. Use it when documentation shows both rheumatoid joint disease and muscle involvement in the hip region, but the side is not specified.
Clinical signs
Typical findings include inflammatory hip pain, stiffness, reduced range of motion, and muscle weakness linked to rheumatoid disease. Clinical features vary; refer to documentation.
When to use this code
Use M05.459 when the provider documents rheumatoid arthritis with rheumatoid myopathy and specifies the hip, but does not identify right or left. This code is appropriate for encounter notes, problem lists, or claims that clearly link the myopathy to rheumatoid arthritis. Check documentation if the muscle disorder is not explicitly attributed to rheumatoid disease.
Do not use for
Do not use this code for hip pain alone, nonspecific myalgia, or rheumatoid arthritis without documented myopathy. If the side is documented as right or left, use the more specific hip code.
Coding tip
Verify that the record links myopathy to rheumatoid arthritis and that the hip laterality is unspecified before assigning M05.459.