Fracture dislocation of the base of the 1st metacarpal.

Fracture dislocation of the base of the 1st metacarpal. It is the fracture that extends through the base of the metacarpal of the thumb to the carpometacrpal joint, with displacement of the metacarpal in relation to the trapezius.


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  • 1 Story
  • 2 Statistics
    • 1 Etiopathogenesis
    • 2 Clinical manifestations
  • 3 Complementary investigations
  • 4 Treatment
  • 5 Source


This fracture was described in 1881, by Edward Hallaran Bennetti , in a communication to a meeting of the British Medical Association in Cork, in which he presented five pieces of unconsolidated fractures, with secondary joint alterations. This article was published in the Dublin Journal of Medical Science in 1882 .


The 1st metacarpal fracture dislocation occurs relatively frequently, and in some statistics it is reported in greater numbers than the base transverse fracture of the 1st metacarpal.

Benneu dislocation fracture, Benneu fracture.


The mechanism of production of the Benneu fracture is similar to that described for the 1st metacarpal base fracture and perhaps a much more pronounced flexion movement occurs in it.

Clinical manifestations

The thumb is shortened at the expense of the metacarpal and the carpometacarpal region is enlarged. The clinical picture is similar to that of the transverse metacarpal fracture.

Complementary investigations

The radiograph shows that there is an oblique fracture through the base of the metacarpal, and that the diaphyseal or distal fragment is displaced up and back, which causes the proximal internal fragment to remain without displacement.


  • Conservative treatment.

The displacement can almost always be reduced by anesthetic manipulation, but it is often difficult to maintain the reduction. Traction is applied to the thumb by exerting pressure on the base of the metacarpal in the abducted position. An attempt should be made to apply a well-molded plastered bandage.

  • Surgical treatment.

Many surgeons are of the opinion that due to the instability of this fracture, it is convenient to use the initial surgical treatment and others leave it for when conservative treatment fails.

After reducing the fracture under radiographic control, the position is maintained by means of a Kirsschner wire passed through the diaphysis of the metacarpal of the thumb to the diaphysis of the metacarpals of the index and middle fingers.


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