Internal oblique radiographs for diagnosis of nondisplaced or minimally displaced lateral condylar fractures of the humerus in children

Background: Several radiographic criteria based on only standard anteroposterior and lateral radiographs have been suggested for predicting the stability of lateral condylar fractures of the humerus in children. Despite adherence to these guidelines, further displacement often occurs after the initial diagnosis and stability assessment. The purpose of this study was to define the usefulness of an internal oblique radiograph in the assessment of these fractures. Methods: We prospectively studied fifty-four lateral humeral condylar fractures in fifty-four children seen between March 2002 and December 2004 to determine the efficacy of internal oblique radiographs in gauging the amount of displacement and the fracture pattern. Plain anteroposterior, lateral, internal oblique, and external oblique radiographs were initially made for all fifty-four patients, and three-dimensional computed tomography scans were performed for seven patients. Results: A large percentage (70%) of the fractures were seen to have different amounts of displacement on the anteroposterior and internal oblique radiographs, and a large percentage (75%) were seen to have different fracture patterns, according to the criteria suggested by Finnbogason et al., on the two views. The internal oblique radiograph was more accurate for demonstrating the fracture gap (thirty cases were seen to have more displacement on that view) and for demonstrating the fracture pattern (twenty cases were seen to have more instability on the internal oblique view). We also confirmed the direction of the fracture line and the location of the fragment more accurately with three-dimensional computed tomography. Conclusions: It is not optimal to evaluate the amount of displacement and the stability of a lateral condylar fracture of the humerus in children on the basis of just anteroposterior and lateral elbow radiographs. Classifications should be based on the greatest displacement seen on at least three radiographic views, especially the internal oblique view. Level of Evidence: Prognostic Level I. See Instructions to Authors for a complete description of levels of evidence.