抄録
Meniscal cysts are uncommon, especially in children. We report a case of lateral discoid meniscus with meniscal cyst in a four-year-old boy. The patient was referred to our department because of limited range of motion in the right knee without any apparent cause. He had slight soft tissue swelling on the anterolateral side and 20 degrees of knee extension limitation. Physical examination showed no tenderness over the anterolateral joint line or disappearing sign. The McMurray test was negative and ligamentous instability was not evident. Magnetic resonance imaging (MRI) showed lateral discoid meniscus with a 13×7-mm meniscal cyst. MRI also showed a high-intensity area through the lateral meniscus body in the T2-weighed image, which was connected to the meniscal cyst. At arthroscopy, a 15-mm longitudinal tear of the complete type in the lateral discoid meniscus was repaired with two FasT-Fix®. We performed both arthroscopic partial meniscectomy and open cystectomy through a small anteromedial incision. After a postoperative period of seven months, there was no evidence of cyst recurrence. We consider that this case of meniscal cyst in a young patient is an interesting one from the viewpoint of etiology.
