Mason classification of radial head fractures

The Mason classification ( sometimes known as Mason-Johnston classification) is used to classify radial head fractures and is useful when assessing further treatment options ^1-2.

• type I: non-displaced radial head fractures (or small marginal fractures), also known as a "chisel" fracture

• type II: partial articular fractures with displacement (>2 mm)

• type III: comminuted fractures involving the entire radial head

  • IIIa: fracture of the entire radial neck, with the head, completely displaced from the shaft

  • IIIb: articular fracture involving the entire head, consisting of more than two large fragments

  • IIIc: fracture with a tilted and impacted articular segment

• type IV: fracture of the radial head with dislocation of the elbow joint

In general type I injuries can be treated conservatively whereas type II injuries require open reduction and internal fixation (ORIF). Type III injuries often require early complete excision of the radial head ².