The bone is empty inside many diseases can cause, clinically more common are the following: 1, very serious osteoporosis in the elderly. 2, diseases in bone tumors, whether benign bone tumors or malignant bone tumors, can lead to reduced density or bone destruction of the femoral head, common are bone cysts, bone giant cell tumors or osteosarcoma, etc. 3, there is a basic fracture, even after systematic treatment but there is bone discontinuity and a large gap at the fracture end. 4, there is a metastatic tumor of the bone, there are malignant tumors in other parts of the body reaching advanced stage and invading the bone leading to bone destruction, commonly in the lumbar spine or pelvic area. Therefore the bone is empty inside, just a manifestation of bone lesion, need to do further examination to clarify the underlying disease in order to have the means of symptomatic treatment.