Radiographic landmark for humeral head rotation: A new radiographic landmark for humeral fracture fixation

Background There is no definite radiographic landmark in plain radiographs for proximal humeral rotation, which is an important parameter for avoiding rotational malalignment during fracture fixation. Here, we used radiographic images of cadaveric humeri to determine whether the landmark of the crest of lesser tuberosity (CoLT) in plain radiographs could be used to determine humeral rotation. Methods Twenty adult cadaveric humeri were collected and seven consecutive radiographic anteroposterior views (45°, 30°, 15° internal rotation; neutral rotation; and 15°, 30°, 45° external rotation) were obtained for each specimen. Results The proportional distance (PD) of the CoLT landmark relative to the humeral head was measured and analysed. The mean PDs of the CoLT landmark were 10.2%, 17.9%, 25.6%, 35.9%, 53.4%, and 62.9% of the diameter of the humeral head, corresponding to 45°, 30°, and 15° external rotation, neutral rotation, and 15° and 30° internal rotation, respectively. We found significant differences in the mean PDs with humeral rotation. Conclusion The projection of the CoLT in plain radiographs can be used as an important landmark to assess humeral head rotation and will be a useful landmark for rotational control of fracture fixation.