Going up stairs with knee pain may be caused by osteoarthritis of the knee joint, chondromalacia patella, ligament injury, meniscus injury and so on. 1. Osteoarthritis of the knee joint: If the patient has osteoarthritis of the knee joint, due to the wear and tear of the cartilage, there is aseptic inflammation locally, which will lead to the symptoms of knee pain in the process of climbing stairs. 2. Chondromalacia patella: when the patient has chondromalacia patella, it may be related to factors such as chronic strain injury, causing wear and tear of the patellar cartilage, which leads to pain when climbing stairs due to the increase in the force on the knee joint area. 3. Ligament injury: If the medial and lateral collateral ligaments or cruciate ligaments around the knee are injured, it will easily lead to instability of the knee, and the wear and tear will be aggravated when climbing stairs, which will lead to the phenomenon of knee pain. 4. Meniscus injury: when the patient has meniscus injury, when going up the stairs, it will be easy for the femur and tibia to squeeze the damaged meniscus, resulting in the meniscus pulling the surrounding synovial tissue, and appearing to go up the stairs with knee pain. Patients with knee pain when walking up stairs should immediately go to the hospital, clear the cause of the disease and follow the doctor’s instructions for treatment.