metacarpal fractures

Metacarpal fractures are common. Fractures of the metacarpal bones account for 10% of all fractures and 40% of all hand fractures. The lifetime incidence of a metacarpal fracture is 2.5%.

Terminology

Specific names are given to fractures of the base of the first metacarpal (see: fractures of the thumb):

Specific names are given to fractures of the fifth metacarpal:

Epidemiology

Fractures of the 5metacarpal make up 25% of all metacarpal fractures (which equates to 10% of all hand fractures).

Pathology

They are a result of direct or indirect trauma with the nature and direction of the force being directly related to the type of injury. Specific injury patterns include:

  • carpometacarpal (CMC) joint injury
    • metacarpal base fractures and dislocation of the CMC joint
  • metacarpal shaft and neck fractures
    • these are usually a result of axial loading or direct trauma (clenched fist and solid surface); torsional force may also result in this type of injury
  • metacarpal head injury
    • these are intra-articular fractures that result from axial loading or direct trauma; collateral ligament avulsion fractures are caused by forced deviation of the flexed metacarpophalangeal joint (MCPJ).
  • metacarpophalangeal joint dislocations
    • dorsal MCPJ dislocations are the most frequent and a result of forced hyperextension of the digit