Bennett's Fracture

A fracture of the 1st metacarpal base, caused by forced hyperabduction of the thumb

Aetiology

  • Mostly caused by axial force applied to the thumb in flexion

Pathophysiology

  • Fracture can extend into the first carpometacarpal joint leading to instability and subluxation of the joint - often needs surgical repair
  • If missed, the articular cartilage of the CMC joint will degenerate → deformity, dysfunction and arthritis

Clinical presentation

Symptoms

  • Acute pain at base of thumb

Signs

  • Swelling and ecchymosis
  • Tenderness to palpation at CMC joint
  • Pain with motion

Investigations

  • X-ray - AP and lateral

Management

  • Following the fracture, there tends to be a small bony fragment attached to the volar beak ligament (a ligament of the CMC joint)
  • The thumb is surgically reduced onto the bony fragment and fixed, commonly with K wires