Idiopathic chronic gout, right knee, without tophus (tophi)

This code signifies a persistent, long-term inflammatory arthritis affecting the right knee, caused by uric acid crystal deposition, but without the presence of visible or palpable tophi (nodular deposits of uric acid). The "idiopathic" designation indicates that the underlying cause of the elevated uric acid is unknown.

Apply this code when documentation explicitly states chronic gout affecting the right knee, without tophaceous deposits, and the etiology is not secondary to another condition. Supporting documentation would include physician notes detailing the diagnosis, location, chronicity, and absence of tophi.

• Ensure documentation specifies "chronic" gout and the "right knee" as the affected joint.
• Verify the absence of tophi; if tophi are present, a different code from the M1A.06x series would be appropriate.
• Distinguish from acute gout flares; this code is for the chronic form of the disease.