A chondroma growing on the side of the knee of a 9-year-old child is associated with certain risks, such as bone deformity, fracture, cancer, etc. Prompt treatment is recommended. Chondroma is a benign tumor that occurs in the tubular bones of the hands and feet. Chondromas are usually characterized by painless lumps and joint deformities. It is usually not obvious in the early stage, and as the child gets older, this chondroma may also increase in size, leading to bone deformity and affecting the child’s daily activities, as well as pathologic fracture when the lesion is large, as well as the risk of cancer. Therefore, it is recommended that a 9-year-old child with a chondroma on the side of the knee should seek early medical intervention, usually through surgery to remove the chondroma, such as bone grafting, bone tumor resection and other treatments. Specific surgical program is recommended according to their own situation, under the guidance of the doctor to choose. Parents should also be careful not to allow children to do strenuous exercise on a daily basis, so as not to aggravate the condition or induce the appearance of symptoms.