In clinical practice, the phenomenon of clicking in the human leg joints is mostly referred to as a popping sound from the knee joint. Because the knee joint is under negative pressure, the pressure inside the knee joint will gradually increase when moving the knee joint, which will cause the air bubble to grow from small to large and finally rupture, which will cause a popping sound. When the patient develops cartilage hyperplasia in the joint, the joint gap is narrowed, and when the knee joint is moved, the cartilage rubs and wears out, causing a popping sound, accompanied by pain and swelling in the joint, which is a pathological popping sound.