Fracture-separation of the distal end of the humerus in children has been reported infrequently, and may be misdiagnosed as a fracture of the condyle or a traumatic dislocation of the elbow. We discuss eight cases of a seldom reported complication following fracture-separation of the distal end of the humerus. This complication consists of dissolution of the trochlea within three to six weeks postinjury and a defect of the medial or central part of the condyle that develops later. The fractures were severely displaced fracture-separation of the distal end of the humerus with large medial or lateral metaphyseal fragment, but initially misdiagnosed as a fracture of the medial, lateral condyle or a traumatic dislocation of the elbow in six of eight cases. We performed open reduction in six cases because of initial misdiagnosis or because of difficulty in satisfactory closed reduction. We speculated that this complication is due to avascular necrosis of the distal end of the humerus, and that fracture-separation of the distal end of the humerus is more common than reported.