Osteolysis of the Patella

Abstract

A 56-year-old man presented with a 3-day history of pain and swelling of the right knee. He had a history of renal stone, chronic renal failure and liver cirrhosis. He did not have a history of trauma. The right knee showed marked swelling, local heating and tenderness. The serum creatinine level was 1.85 mg/dL (reference, 0.4∼1.5 mg/dL) and uric acid level was 10.1 mg/dL (reference 3.0∼8.3 mg/dL). Acute phase reactants showed elevations including erythrocyte sedimentation rate of 28 mm/hr by the Westergren method, 7.16 mg/dL (reference, 0.0∼0.3 mg/dL) of C-reactive protein. The creatinine clearance (22.6 mL/min, reference 75.0∼125.0 mL/min) and the renal excretion of uric acid (490 mg/day, reference 250∼750 mg/day) were decreased in 24-hour urine anlalysis. AP view of both knees showed an osteolytic lesion with bony defect and fragment on the superolateral portion of the right patella (arrow, Figure 1A). Skyline view showed a similar lesion on the lateral portion of the right patella and