Abnormal band of the lateral meniscus of the knee.

We report 2 cases of an abnormal band of the lateral meniscus of the knee joint. A 23-year-old man complained of mechanical symptoms in both knees and an arthroscopic procedure was performed. We found meniscal abnormalities in the both knees. A 20-year-old man sustained a posterior cruciate ligament injury. In the course of an arthroscopy for his torn posterior cruciate ligament, an abnormal band of the lateral meniscus was seen. It was characteristic that the upper abnormal band was loose and serpentine and connected at the posterior horn and the middle segment of the lower normal lateral meniscus. Arthroscopic resection of abnormal bands successfully eliminated the symptoms. Because of its characteristic appearance and bilaterality, it was evident that this abnormal band was a congenital anomaly.