"Isolated" traumatic radial-head dislocation.
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.
Lincoln
T L
TL
Department of Orthopaedics, University of California at San Diego 92103.
Mubarak
S J
SJ
D002648:Child; D002675:Child, Preschool; D004551:Elbow Joint / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000000981:diagnostic imaging*; D008297:Male; D011859:Radiography; D011884:Radius / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D014457:Ulna / Q000000981:diagnostic imaging; D000092464:Elbow Injuries