Atypical Bennett's fracture-dislocation

Abstract

We herein report an unusual case of a fracture-dislocation of the thumb metacarpal base. The injury consisted of features typical of Bennett's fracture-dislocation of the thumb trapeziometacarpal joint, with additional rotation of the proximal fragment, signifying a greater ligamentous injury. Radiographic features of this injury are discussed together with its pathomechanics. Surgical management was undertaken due to the inherent instability of this injury.

Fig. 1

(a) Lateral and (b) anteroposterior radiographs of the right thumb show a fracture-dislocation of the TMCJ.

Fig. 2

Anteroposterior radiograph of the right hand shows the distal fragment of the fracture-dislocation being pronated and dislocated dorsally.

Fig. 3

(a) Pre-reduction intraoperative photograph shows the distal fragment pronated and dislocated dorsally (A); the dislocated proximal fragment, with the articular surface facing dorsoradially (B); and the articular surface of the trapezium (C). (b) Post-reduction intraoperative photograph shows restoration of a congruent trapeziometacarpal joint.

Fig. 4

Intraoperative radiographs show the fixation with the Synthes^® 2.0 mm modular hand system.

Fig. 5

Anteroposterior radiograph of the right hand shows a typical Bennett’s fracture-dislocation.