If adolescents during the growth and development period have the phenomenon of creaky knees, it is generally a normal physiological phenomenon. If an adult walks with a creaky knee, it may be caused by synovitis, meniscus injury, osteoarthritis of the knee and other diseases. 1. Knee synovitis: patients with knee synovitis will have knee injuries, internal knee joint effusion, friction in the knee joint when walking, so the knee will appear creaking sound, accompanied by pain and swelling of the knee joint. 2. Meniscus injury: due to strenuous exercise, weight bearing and other external factors will lead to knee meniscus injury, joint swelling, pain and activity limitation, joint fluid and free body friction in the movement, so the knee will appear creaking sound when walking. 3. Knee osteoarthritis: due to the knee joint hyperplasia, hyperplasia stimulates the surrounding soft tissues, friction occurs between the bones when walking, so the knee will appear creaking sound. Patients who find that the knee walking creaking, at the same time there are other symptoms of discomfort, should seek medical treatment as soon as possible to avoid delays in the condition.