Children’s knee pain in the place of bending, consider that it may be related to malnutrition, knee joint disease, growing pains and other reasons. 1. Malnutrition: Children are in the critical period of growth and development. If they cannot get enough calcium, vitamin D and other nutrients from their diet, it may lead to muscle twitching and cause pain where the knee bends. 2 Knee disease: When a child walks or plays sports, he or she may wear down the patella joint surface. If damage occurs to the patellar joint surface may cause pain. Trauma, infection, and tuberculosis may also lead to synovitis of the knee. Localized inflammatory stimuli may lead to swelling, pain, and limited movement of the joint. 3. Growing pains: they mostly occur during the child’s rapid growth period, mostly in the arms and legs. Children’s knee pain where it bends may also be related to other causes (such as aseptic synovitis), it is recommended to go to the hospital as soon as possible in order to clarify the cause of the disease and treat it as soon as possible.