Monteggia fracture-dislocations are classified by the Bado system. Bado type I injuries are characterized by a proximal ulnar fracture with anterior dislocation of the radial head. This is due to a forceful pronation injury of the forearm and is the most common type. Bado type II injuries are "reversed" Monteggia fracture-dislocation injuries. Here, there is posterior angulation of the ulnar fracture site and posterior dislocation of the radial head. Bade type III and IV injuries are rare.
AP radiograph of the elbow. This shows a comminuted fracture of the proximal ulna.
Lateral radiograph of the elbow. This demonstrates posterior dislocation of the radial head, a "reversed" Monteggia injury (Bado type II).
