The pattern of this fracture is characterized by a partial epiphyseal separation (Salter-Harris III) on the lateral side of the distal humerus. The classification is independent of fragment size and displacement.
This fracture pattern is extremely rare; most lateral condyle fractures are Salter-Harris IV fractures with a metaphyseal wedge.
In the infant, or very young child, it can be difficult to distinguish this injury from a low transphyseal fracture (Salter-Harris I).
Radiologically this fracture is difficult to diagnose if the child is very young, or the fracture is minimally displaced. The fat pad sign is an important indirect indicator of an intraarticular lesion.
Ultrasonography can help verify the diagnosis.
Arthrography may be used when diagnosis is in doubt.
MRI under sedation can sometimes be indicated in very young children.