Double fractures of the ulnar radius are most often seen in adolescents. Direct and indirect (conveying or twisting) violence can cause double fractures of the ulnar flexor shaft. The fracture is associated with local swelling, pain, limb deformity, forearm rotation dysfunction, and bone rubbing sounds in complete fractures. The ulnar-radial double fracture is the second most common fracture of the forearm, after the distal radius fracture, and can occur with lateral displacement, overlapping rotation, and angular deformity, which is more complicated to treat, and the types of fractures caused by different forms of violence are different. Double fractures of the ulnar radial trunk can be treated with closed manipulation and external splinting, regardless of their location and type. If the fracture end can be repositioned but its position is not easily maintained, closed steel pin penetration internal fixation can be performed under anesthesia. It is important to restore the axis of the ulnar radius and the bone gap between the two bones during treatment, otherwise the rotational function of the forearm will be affected. Surgical treatment of ulnar radius fracture is limited to those with poorly repositioned fracture ends, loss of bone gaps or suspected soft tissue embedment in the fracture end. (a) Double fracture of the ulnar radius 1. Direct violence: mostly seen in blows or machine injuries. The fracture is transverse or comminuted, and the fracture line is in the same plane. 2. Indirect violence: when the palm of the hand touches the ground after a fall, the violence is conveyed upward to the middle or upper 1/3 of the radius fracture, and the residual violence is transferred to the ulna through the interosseous membrane, resulting in ulnar fracture. So the position of the fracture line is low. The radius is transverse or jagged, and the ulna is short and oblique with displaced fracture. 3. Torsional violence: the fracture is caused by external force while the forearm is subjected to torsional external force. When the body is tilted on the same side during the fall, the forearm is overly rotated forward or backward and a double bone spiral fracture occurs. Most of the fractures are oblique from the upper ulna to the lower radius, and the fracture lines are in the same direction, with the ulnar stem fracture line on top and the radial fracture line on the bottom. (ii) Radial trunk fracture Most of the fractures are green branch fractures in young children. In adults, when the upper 1/3 of the radial stem is fractured, the biceps muscle attached to the radial tuberosity and the posterior rotator muscle attached to the upper 1/3 of the radius cause the proximal segment of the fracture to rotate and displace posteriorly. In the middle 1/3 or lower 1/3 of the radial trunk fracture, the fracture line is below the stopping point of the anterior rotator muscle, and due to the equal strength of the anterior and posterior rotator muscles, the proximal segment of the fracture is in a neutral position, while the distal segment of the fracture is pulled by the anterior rotator muscle and displaced anteriorly by rotation, and there is not much overlapping displacement in simple radial trunk fractures. (C) ulnar trunk fracture Simple ulnar trunk fracture is rare, mostly occurring in the lower 1/3 of the ulna, caused by direct violence, with less displacement of the fracture end. Clinical manifestations】 Patients with this disease mainly show local swelling, deformity and pressure pain, there may be bone rubbing sound and abnormal activity, and forearm activity is limited. In children, the fracture is often a green branch fracture with angular deformity and no displacement of the bone end. Sometimes combined with injury to the median nerve or ulnar or radial nerve, attention should be paid to the examination. It is also called both tibial fractures of the hand bone or double fractures of the forearm. Direct or indirect violence can cause double fractures of the radial and ulnar trunks, and the fracture site mostly occurs in the middle 1/3 and lower 1/3 of the forearm. The radial and ulnar trunk fractures are associated with local pain and swelling, loss of forearm function, and increased pain with movement. In complete fractures with displacement, the forearm may be shortened, angulated, or rotated, with bone rubs and loss of forearm rotation. In open fractures, the fracture end may poke out of the skin, but the wound is usually small and the exposed fracture end may sometimes retract into the wound on its own. Diagnosis】 Post-traumatic forearm pain and movement disorders can be clarified by X-rays. The radiographs should include the elbow and wrist joints to understand whether there is rotational displacement and upper and lower ulnar radial joint dislocation. 【Treatment】 Double fractures of the ulnar radial stem require correct alignment of the proximal and distal segments of the two bones, correction of the four deformities, and restoration of the physiological length of the two bones. This kind of fracture is more difficult to reset, and it is easily displaced after reset. However, the combined experience of Chinese and Western medicine in treating the fracture proves that the manual orthoprosthesis and proper external fixation can cure most cases. The treatment of pure ulnar or radial fracture is the same. 1.Resetting is difficult and demanding, and it is easy to dislocate after resetting. (1) Children’s green branch fractures are mostly angular deformities, which can be corrected by gentle traction under proper anesthesia and plaster fixation for 6 to 8 weeks. The angular deformity can also be corrected with a plaster wedge incision. (2) For displaced fractures, longitudinal traction is used to correct the overlap and angular deformity, and the forearm is placed in a rotated posterior position under continuous traction if the upper 1/3 of the fracture is tied (above the stop of the pronator teres); for the lower 1/3 of the fracture (below the stop of the pronator teres), the forearm is placed in a rotated neutral position to correct the rotational deformity. The fracture is then compressed at the fracture site to restore interosseous membrane tension and normal clearance, and finally the fracture end is fully aligned. After repositioning, the fracture is fixed with a long-arm plaster tube for 8 to 12 weeks, and the plaster is cut and released immediately after molding. During fixation, the blood circulation of the extremity should be observed to prevent ischemic contracture. After the swelling subsides, adjust the external fixation tightness in time and pay attention to the observation and correction of fracture re-displacement. 2.Open internal fixation is suitable for those who have failed in manual repositioning or have difficulty in fixation after repositioning; multiple fractures of the upper limb; interosseous membrane rupture; open fractures with light contamination for a short period of time after injury; bone discontinuity or deformity healing with limited function.