患者女性 ,3 3岁。以右膝关节间断发作性功能障碍半年余主诉就诊。患者半年前无明显原因突然出现“右膝关节交锁” ,膝关节屈曲后突然不能伸直伴疼痛 ,经自行活动后又突然缓解 ,伸直运动恢复正常 ,此后经常有类似发作。近一月来发作频繁 ,经ＭＲＩ及Ｂ超诊断为“右膝关节内实质 Patient female, 3 3 years old. To the right knee intermittent episodes of sexual dysfunction more than six months the main complaint. Six months ago, no obvious reason for the sudden emergence of “right knee joint lock,” suddenly after knee flexion can not be straight with pain, after a sudden relief by their own activities, exercise straight back to normal, and thereafter often have similar attacks. Attacks have been frequent in recent January and diagnosed by MRI and B-ultrasound as "the essence of the right knee joint