CORONAL SHEAR FRACTURES OF THE DISTAL END OF THE HUMERUS

We identified a shear fracture of the distal articular surface of the humerus, with anterior and proximal displacement of the capitellum and a portion of the trochlea, in six patients (five female and one male) . The average age of the patients was thirty-eight years (range, ten t o sixty-three years). Each fracture was the result of a fall from a st anding height. A characteristic radiographic abnormality, which we hav e termed the double-are sign, was seen on the lateral radiograph of ea ch patient and represented the subchondral bone of the displaced capit ellum and the lateral trochlear ridge. All patients were managed with open reduction, internal fixation, and early motion of the elbow. The average duration of follow-up was twenty-two months (range, eighteen t o twenty-six months). The fracture united in all patients at an averag e of six weeks (range, four to nine weeks), without radiographic evide nce of osteonecrosis of the fracture fragment. Flexion of the elbow av eraged 141 degrees (range, 130 to 150 degrees), with an average flexio n contracture of 15 degrees (range, 0 to 40 degrees). Pronation of the forearm averaged 83 degrees, and supination averaged 84 degrees. All patients had a good or excellent functional result, according to the e lbow-rating scale of Broberg and Morrey.