Greater trochanter percussion pain is a clinical symptom of traumatic femoral head necrosis. So, what are the causes of large rotor percussion pain? Below, briefly introduce several reasons: 1, clear trauma history Fracture of the femoral neck, the most significant among the causes of traumatic is the femoral neck fracture. It is a more serious injury, and after the injury most of them have to go to the examination, take X-ray film, adopt traction, reset, fixation and surgical treatment, etc. Therefore, the medical history is clear, but it should also be pursued and recalled. Patients can even describe the cause and location of injury, treatment, etc., therefore, the exact value of the diagnosis reference. 2.The site of injury is clear. Where the injury is caused by trauma, most of them have unilateral onset of femoral head, and the onset must be on the injured side, rarely bilateral onset, unless the injury is bilateral and bilateral necrosis may occur, which is different from other causes. 3.Recall of treatment Patients who had hip trauma must have gone through systematic treatment. For example, whether it has been traction, repeated reset, surgery, etc. The effect of treatment is good or bad, such as whether the reset is satisfactory, whether there is no reset, whether the deformity is healed, whether the internal fixation is still in the body, etc. All provide important materials for timely and correct diagnosis.