A New Pediatric Monteggia Fracture Type 4 Variant

Monteggia fracture-dislocations are rare and complex injuries that usually involve a fracture of the proximal ulna associated with a proximal radioulnar and radiocapitellar joint dislocations. These injuries comprise <1% of all pediatric forearm fractures. We report on a pediatric Monteggia fracture-dislocation variant that included an irreducible divergent ulnohumeral joint dislocation, an irreducible anterior radial head dislocation, and a proximal and distal radius and ulna fracture.

A 6-year-old female came to our emergency room with a right elbow and forearm pain and deformity after a fall from a slide on the same day. X-rays revealed a divergent ulnohumeral joint dislocation, an anterior radiocapitellar joint dislocation, a proximal radioulnar joint dislocation, and a proximal and distal ulna and radius fracture. Closed reduction under sedation in the emergency room was not successful, with persistent ulnohumeral, ulnoradial, and radiocapitellar joint dislocations. The patient was taken to the operating room the next morning. She underwent open reduction and internal fixation of the proximal ulna fracture with a one-third tubular locking plate, and radial head dislocation open reduction. A stable reduction of the ulnohumeral joint was only possible after the fixation of the proximal ulna fracture. The most stable position for the radiocapitellar joint after its open reduction was at 70o of elbow extension and full forearm supination; the patient was casted in that position for 6 weeks.

Pediatric Monteggia fracture-dislocations are rare and complex childhood fractures, and new variants of this injury can have even more complex presentations. Open reduction and stable internal fixation addressing all components of this injury will lead to an excellent outcome.