ABSTRACT
We present here a case of gouty synovitis of the knee in a patient with partial hypoxanthine-guanine phosphoribosyl transferase deficiency (Kelley-Seegmiller syndrome), which is an inherited purine metabolic disorder. Magnetic resonance images and computed tomography showed a diffuse mass with stippled calcification around the posterior cruciate ligament (PCL) in the posterior intercondylar notch. Arthroscopic examination revealed that the articular surfaces and menisci in the affected knee were almost completely covered with white chalky monosodium urate (MSU) crystals. The diffuse mass around the PCL was composed of proliferative synovial villi covered with MSU crystals that looked like "snow covered trees". Arthroscopic total synovectomy was performed. The posterior trans-septal portal was especially useful for removal of the proliferative villi around the PCL. To our knowledge, this is the first report of arthroscopic examination in a patient with Kelley-Seegmiller syndrome.