Adolescent knee pain may be related to calcium deficiency, trauma, infectious diseases, bone and joint tumors and other factors. 1. Calcium deficiency: Teenagers may suffer from calcium deficiency due to insufficient calcium intake and increased calcium consumption, which may cause teenagers to suffer from lack of energy, weakness of lower limbs, leg cramps and knee pain. 2. Trauma: when teenagers’ knees are hit by external force or when the joints are over-extended and twisted, knee pain can be triggered, which may be accompanied by local redness and swelling. 3. Infectious diseases: common pathogenic bacteria include staphylococcus, tuberculosis, etc. Teenagers can be invaded by bacteria into the knee joint, which leads to the phenomenon of teenage knee pain. 4. Bone and joint tumors: common diseases include osteochondroma, chondrosarcoma, etc., which can also cause knee pain, and may be accompanied by local pain, activity limitation and other phenomena. In addition, there are many other reasons that can cause knee pain in adolescents, and it is recommended that the patients should consult the doctor in time to find out the cause of the disease and follow the doctor’s instructions for treatment.