Abstract
An 18-year-old woman had locking in the right knee joint several times a month and later complained of knee pain during bowling game. She noticed swelling on her right knee for a month after the pain first occurred. Her knee lacked 20°of extension on locking. She was admitted with a one-and-a-half year history of knee locking. Clinical examination showed no significant findings. The arthroscopic procedure demonstrated a soft substance such as a tumor which originated from the posterior part of the medial surface of the lateral femoral condyle and extended on the lateral tibial plateau along the lateral edge of the anterior cruciate liga-ment. After resection, she had complete relief. Histologic findings identified it as ligamentous tissue. The distal superficial layer was lined with dense connective tissue, and necrotic tissue was surrounding abundant blood vessels in the distal profound area. These findings suggested that the knee locking occurred as a result of an isolated partial tear of the anterior cruciate lig ament.
