ICD-10 Code M05.679 – Rheumatoid arthritis of unspecified ankle and foot with involvement of other organs and systems (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.679 – Rheumatoid arthritis of unspecified ankle and foot with involvement of other organs and systems
What it is
This code identifies rheumatoid arthritis affecting an unspecified ankle and foot, with documented involvement of other organs or systems. Use it when the record supports rheumatoid disease at that joint location and extra-articular involvement.
Clinical signs
Typical findings include inflammatory joint pain, swelling, stiffness, and reduced motion in the ankle or foot. Clinical features vary; refer to documentation for the specific extra-articular organ or system involvement.
When to use this code
Use this code when the provider documents rheumatoid arthritis in an unspecified ankle and foot and also notes involvement beyond the joints. The chart should support both the anatomic site and the systemic manifestation. If the record does not clearly identify the site or extra-articular involvement, check documentation.
Do not use for
Do not use this code for rheumatoid arthritis limited to the joint alone without other organ or system involvement. It is also not appropriate when the ankle or foot site is different or more specific coding is documented.
Coding tip
Verify that both the unspecified ankle/foot site and the extra-articular involvement are explicitly documented before assigning M05.679.