Thigh muscle atrophy may be caused by traumatic fracture. The disuse muscular atrophy caused by long-term fixation may also be caused by the decline of muscle dominance and muscle activity caused by nerve injury. If it is caused by trauma, fracture or long-term braking, it can be recovered after a period of active functional exercise. If the atrophy is caused by paralysis of thigh muscles due to nerve injury, the treatment effect is not very ideal. In the acute phase, nerve anastomosis can be performed. After nerve function recovery, thigh muscle atrophy will gradually recover; If the nerve function cannot be recovered, the effect of passive or active exercise is not ideal. Thigh muscle atrophy may also be caused by osteoarthritis, which can strengthen quadriceps exercise to alleviate the symptoms of muscle atrophy.