抄録
A 30-year-old female with idiopathic hematoma in the isolated suprapatellar pouch of the knee was treated in our hospital.
She experienced left knee pain and realized swelling at the proximal area to the patella from 1997. She had hardly been able to sit down and ascend the stairs. We could touch the click at the proximal area to the patella at the 20 degrees flexed position. Though there were no obvious abnormal findings on plain roentgenographs, there was an isolated cystic leision enhanced by arthrography in the puncture of the suprapatellar pouch. It interrupted into the P-F joint at the 20 degrees flexed position. On Gadolinium enhancement of magnetic resonance imaging, the peripheral area of the cyst showed clear contrast.
In May 1999, we found the plica to be Sakakibara type C of the knee joint and diffuse mild synovitis in the knee joint by arthroscopy examination. We resected the isolated cyst and found bloody fluid inside. The inner surface of the capsule was very smooth, there were no findings similar to a nodule usually found in pigmented villonodular synovitis. On the other hand, there were no angioendotheliocells and hyperplastic inflammatory cells.
We therefore diagnosed hemorrhagic bursitis in the isolated suprapatellar pouch. At 5 months after the operation, the patient felt no knee pain and there were no recurrent findings.
