Rheumatoid nodule, left knee

This code identifies the presence of a rheumatoid nodule specifically located on the left knee. Rheumatoid nodules are firm, non-tender subcutaneous lumps that commonly occur in patients with rheumatoid arthritis, often over pressure points or extensor surfaces. Their presence indicates a more severe or active form of the underlying autoimmune disease.

Use this code when documentation clearly indicates a rheumatoid nodule is present on the patient's left knee. This typically occurs in patients with a confirmed diagnosis of rheumatoid arthritis. Supporting documentation should include physical exam findings describing the nodule's location and characteristics, or imaging reports confirming its presence at the specified site.

• Ensure the laterality (left knee) is explicitly documented; do not assume.
• Always code the underlying rheumatoid arthritis (e.g., M05.xx or M06.xx) as the primary diagnosis when a rheumatoid nodule is present.
• Differentiate from other subcutaneous nodules not associated with rheumatoid arthritis, which would be coded differently.