Alteration of Baumann's angle by humeral position: implications for treatment of supracondylar humerus fractures.

To determine the effects of limb positioning on Baumann's angle, we made a controlled radiographic study of a 6-year-old cadaver upper extremity specimen. Radiographic measurement of Baumann's angle was obtained at 10 degrees increments of humeral rotation from 40 degrees of internal rotation to 40 degrees of external rotation. These measurements were obtained with the humerus parallel to the x-ray cassette and with the humerus flexed 30 degrees from the cassette. Measurement of Baumann's angle with radiographs obtained with the humerus parallel to the x-ray cassette was associated with less variation in the measured angle (6 degrees of change for every 10 degrees of rotation). The relevance of these findings in management of supracondylar fractures is discussed.