Going upstairs with creaky knees may be caused by physiological popping, or it may be caused by degenerative diseases of the knee joint, meniscus injuries and other pathological factors. 1. Physiological popping: there are oxygen, carbon dioxide and other gases in the joint capsule of the knee joint, when going upstairs due to repeated knee extension and flexion movements, resulting in increased pressure in the joint cavity, the gases in the joint capsule are extruded by the pressure, and rupture outside the joint capsule to produce a loud sound, which is known as physiological popping. Physiologic popping is short, crisp and not accompanied by joint pain. 2. Pathological factors: due to age, long-term wear and tear, the knee joint may appear degenerative lesions, degenerative lesions will lead to the formation of intra-articular bone cumbersome, synovial membrane hyperplasia and other pathological changes, the impact and wear and tear of the joints increase when going up the stairs, and may also appear sound. When meniscus injury occurs due to various reasons, the wear and tear of articular cartilage increases, and the above symptoms may also occur. There may be other reasons for the creaking of the knee when going upstairs, so it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment under the guidance of the doctor.