The causes of knee bone rattling generally include physiological popping, meniscus injury, knee osteoarthritis and chondromalacia patella. 1. Physiological popping: physiological popping is the knee joint in the process of activity, the knee ligament with the bony structure of the protruding parts of the sliding produced, no pain and other uncomfortable symptoms, without special treatment. 2. Meniscus injury: after meniscus wear or tear, popping will occur in knee joint activities, accompanied by knee pain, especially when going up and down stairs. 3. Osteoarthritis of the knee: caused by degenerative changes and osteophytes of the knee, besides popping, it mainly manifests as swelling and pain of the knee, stiffness, and limitation of activities. 4. Chondromalacia patella: caused by chronic damage to the cartilage surface of the patella, mainly manifested as knee pain and weakness, aggravated by going up and down stairs or squatting. Knee bone ringing may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, give targeted treatment or treatment.