Bennett Fracture Workup

Updated: Sep 07, 2018
  • Author: Mark E Baratz, MD; Chief Editor: Harris Gellman, MD  more...
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Workup

Imaging Studies

Obtain standard posteroanterior (PA), lateral, and oblique radiographs in patients with suspected fractures or dislocations of the thumb. Traction radiography may be used to assess the degree of comminution in appropriate fractures (eg, Bennett, Rolando, comminuted metacarpal base fractures; see the images below).

Radiograph of a Bennett fracture. Radiograph of a Bennett fracture.
Rolando fracture. This is differentiated from a Be Rolando fracture. This is differentiated from a Bennett fracture because of the presence of intra-articular comminution.

Radiographs of the carpometacarpal (CMC) joint are obtained by placing the palmar surface of the hand flat on the imaging plate for a true lateral view, allowing accurate assessment of the CMC joint. Pronate the hand and wrist approximately 20-30º, and direct the imaging beam obliquely at 15º in a distal-to-proximal direction centered over the trapeziometacarpal joint.

A broken V sign may be present on the lateral radiograph, indicating disruption of the normal V that is formed by the radial aspect of the trapeziometacarpal articulation. This may indicate undetected CMC joint subluxation.

Tomography or computed tomography (CT) can help define the degree of comminution within a fracture, as well as suspected impaction of the articular surface.