A rare but radiographically recognizable cause of an irreducible hip fracture-dislocation.

Hip dislocations are emergently reduced to decrease the chance of avascular necrosis of the femoral head. However, in some situations, the dislocation may be irreducible by a closed technique. Rarely, the fractured femoral head may become perched on an intact acetabulum, leading to an irreducible fracture-dislocation. This rare type of irreducible fracture-dislocation demonstrates unique physical and associated radiographic findings. These fractures are important to recognize early, as attempts at closed reduction can lead to femoral neck fractures.