Idiopathic chronic gout, right knee, with tophus (tophi)

This code signifies a chronic, primary form of gout affecting the right knee, characterized by the presence of tophi. Tophi are deposits of uric acid crystals that form under the skin or in other tissues, indicating long-standing and poorly controlled hyperuricemia.

Apply this code when documentation explicitly states idiopathic chronic gout involving the right knee with evidence of tophaceous deposits. This is typically used for patients with a confirmed diagnosis of chronic gout and visible or palpable tophi in the specified joint.

• Ensure documentation specifies "idiopathic" or "primary" chronic gout to differentiate from secondary forms.
• Verify the laterality (right knee) and the presence of tophi are clearly documented.
• Do not use this code for acute gout flares or chronic gout without tophi; separate codes exist for those conditions.