It has been almost one year since the femur fracture of thigh, and the buttock is big on one side and small on the other side, which may be caused by post-fracture deformity healing and muscle wasting atrophy. 1. Post-fracture deformity healing: After femur fracture, there is no active treatment, or the treatment is not proper, or the part is subjected to violence again, which leads to deformity healing after fracture, destroying the physiological structure of the affected side, causing the buttocks to be big on one side and small on the other side. 2. Muscle wasting atrophy: after femur fracture, long time traction external fixation, or after fracture due to pain, patients do not move the affected side for a long time, which leads to the affected side of the buttock muscle gluteus maximus, gluteus medius and other wasting atrophy, ultimately leading to the buttocks appear one side of the big and one side of the small situation. After thigh femur fracture, the appearance of the buttocks is asymmetrical, you can go to the regular hospital to review the X-ray of the lower limbs, and find a doctor to check the body, in order to clarify the cause, and then do the appropriate treatment.