Dislocations of sternal segments in children are extremely rare lesions; only seven sterno-manubrial dislocations have been reported in the literature. We present a case of posterior sterno-manubrial dislocation in a 9-year old gymnast exercising on parallel bars. We preferred performing an open reduction and plate stabilization using an angular stable implant, because of pain and respiratory distress. This technique of stabilization has not been described in the literature before and present the advantage of combining a high stability with a reduced risk of iatrogenic retrosternal injury. The plate stabilization led to an immediate amelioration of symptoms. The plates could be removed 4 months after initial treatment. The boy rapidly regained his sporting capabilities.