Knee pain going up and down stairs and squatting pain may be caused by meniscus injury, knee osteoarthritis, osteophytes and other reasons. 1. Meniscus injury: if in some kind of sports activities, so that the knee is subjected to violent impact, may lead to knee meniscus damage to make the joint swelling, and meniscus synovial rim has a relatively rich nerve, sensory endings, the knee is easy to go up and down the stairs and crouch down to the synovial rim of the meniscus, stimulate the peripheral nerve endings caused by the pain of the symptom. 2. Knee osteoarthritis: when patients overwork, trauma, infection and other factors lead to knee cartilage damage, may cause aseptic inflammation of the knee joint, the knee up and down the stairs and squatting flexion and extension easily stimulate the inflammatory factor, so that the patient’s knee joint pain symptoms. 3. Osteoplasia: If the symptoms of knee pain on stairs and squatting occur in the elderly, it may be due to osteophytes in the knee joint of the elderly, which leads to an increase in the internal pressure of the knee joint of the patient’s leg, and the osteophytes may irritate the tissues around the knee joint to cause pain when the knee is moving up and down stairs and squatting, causing pain symptoms. Knee pain going up and down stairs and squatting pain may also be caused by other reasons, the patient should promptly go to a specialized hospital, under the guidance of the doctor for systematic treatment.