Dislocation of the child’s arm, also known as radial tuberosity subluxation, is one of the common elbow injuries in infants and children. The age of onset is 1-4 years old, with the highest incidence at 2-3 years old, and is most likely to occur when adults pull the child’s arm up and down steps in daily life. The common mechanism of injury is a violent pull on the upper extremity or a minor elbow sprain, and children with this disease often have a history of being pulled on the upper extremity, such as: using both hands to pull the child’s wrist to fall during walking; pulling the child’s wrist by the cuffs when wearing clothes; rolling in bed, the body presses the upper extremity under the body, forcing the elbow joint to overstretch and other external forces. After the injury, the child cries and is reluctant to lift and move the affected limb and to be touched by others. The elbow joint is in extension and the forearm is rotated forward and down. The arm is not red or swollen, but there is significant pressure pain on the outside of the elbow joint. Treatment is not complicated, but requires a specialized clinician. The method is to first calm the child, hold the child’s elbow with one hand and press the thumb in the position slightly in front of the lateral radial tuberosity, hold the child’s wrist with the other hand, first traction, external rotation and hyperextension of the forearm, while the thumb gently pushes the radial tuberosity and flexes the elbow joint to the maximum, then internally rotate the forearm and straighten the elbow joint, a resetting sound can be felt, and the elbow joint can be extended and flexed 2-3 times if necessary. After the resetting, the child is asked to grasp the object and touch the head with his hands, and if the elbow joint is flexible and no longer cries, the resetting is successful. After the age of 4-6 years, the head of the radius grows up and the ligaments of the elbow joint become mature, so it is not easy to dislocate.