Can osteosarcomas grow on the knee? In fact, the locations where osteosarcomas commonly appear are indeed near the knee. There are mainly three common sites: the most prevalent is the distal end of the femur, the lower part of the thigh bone. The second most common site is the proximal end of the tibia. The third is the proximal end of the humerus. Therefore, osteosarcomas usually do grow near the knee. What are the symptoms of an osteosarcoma? The symptoms of osteosarcoma include, first, localized pain, which is a constant pain that persists, worsens, and does not alleviate, often causing night pain, and many patients do not feel pain during the day, only at night. The second symptom is a localized lump, generally spindle-shaped, with an increased skin temperature over the surface, and even distended veins due to the tumor restricting nearby joint movement. The third symptom is the appearance of cachexia or wasting syndrome throughout the body. The fourth point is that the growth of the osteosarcoma leads to erosion of the bone and eventually pathologic fractures. Thus, the likelihood of osteosarcomas appearing near the knee is very high, and many patients typically come to the hospital because of painful lumps near the knee, and then, after examination, the diagnosis is confirmed.