Monteggia Fracture Workup

Updated: Sep 01, 2022
  • Author: Floriano Putigna, DO, FAAEM; Chief Editor: Murali Poduval, MBBS, MS, DNB  more...
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Laboratory Studies

Laboratory studies may be obtained as indicated by the patient's medical history, to assist with anesthesia and perioperative management.


Imaging Studies

Plain radiography is indicated. Views of the forearm in orthogonal planes (planes at 90° to each other) are needed with the wrist and elbow joints included. The evaluating physician should also obtain separate radiographs of the elbow to assess the proximal radioulnar joint (PRUJ), the ulnohumeral articulation, and the radiocapitellar joint.

On radiographs, the ulna fracture is usually obvious, but the findings associated with the radial head dislocation may be subtle and overlooked. In order to assess the radiocapitellar joint, a line is typically drawn parallel to the long axis of the radius. This line should point directly at the capitellum on any projection of the elbow. The radial head dislocation almost always points in the same direction as the apex of the ulna fracture. In children, recognizing a plastic deformation of the ulna, which may also lead to radial head dislocation, is important.

Variations of the traditional radiocapitellar line have been described. In a study comparing lines drawn along the longitudinal center of the radial neck (N-line), along the radial shaft (S-line), and through the midpoints of the proximal and distal radial physes (P-line), Wang et al found that the P-line was least likely to miss the capitellum on both AP views and lateral views and most frequently passed through the central third of the capitellum on both AP views and lateral views. [17]