"Isolated" traumatic radial-head dislocation

J Pediatr Orthop. Jul-Aug 1994;14(4):454-7. doi: 10.1097/01241398-199407000-00006.


A delay in diagnosis of a traumatic radial-head dislocation in the absence of a concurrent ulnar fracture is common. Published reports of this injury imply an isolated injury to the radius without involvement of the ulna. This hypothesis is challenged by a retrospective study of all cases over an 8-year period that demonstrates an identifiable injury to the ulna in every case. A new radiographic sign, the "ulnar bow sign," is described to assist in the proper recognition of this injury pattern. A radial-head dislocation or subluxation should be suspected if the posterior border of the ulna on a true lateral radiograph deviates > 0.01 mm from a straight line.

MeSH terms

  • Child
  • Child, Preschool
  • Elbow Joint / diagnostic imaging
  • Elbow Joint / injuries*
  • Female
  • Humans
  • Joint Dislocations / diagnostic imaging*
  • Male
  • Radiography
  • Radius / diagnostic imaging
  • Retrospective Studies
  • Ulna / diagnostic imaging