There are many diseases that can cause a ringing sound when the knee squats, the following diseases are common: 1, physiological ringing: the knee joint is in a position, after a sudden change of position, can occur without pain occasional ringing, the patient does not need to worry about this, belongs to the normal physiological response. 2, osteoarthritis: if the severe osteoarthritis has lost the cushioning role of the meniscus, the joint in bending without the protection of the meniscus, the bone surface and the friction between the bone surface, you can hear the ringing. 3, the presence of free bodies inside the knee joint: there will also be irregular ringing, but the sound is usually small, and the symptoms can disappear through surgery. 4, joint impingement syndrome: patients with poor joint alignment will generally experience joint Most of them are accompanied by pain and need to be seen in hospital.