Abstract
Clavicle fractures account for 44–66% of shoulder fractures. Evaluating degree of shortening is important when deciding between operative and non-operative treatment. The clavicle of a skeleton was marked at midpoint and junctions of the thirds along its superior surface. Antero-posterior (AP) and 30-degree upshot radiographs were taken. Images were analysed measuring distance between markers. In both AP and upshot images there were apparent discrepancies between lengths of each third and half. The main differences in apparent length appear in the measurement of the thirds of the clavicle. The AP made the medial third shorter compared to the middle and lateral third, whereas the upshot appeared to make the medial third shorter than the middle third with the lateral third shorter again. This study supports the theory that there is parallax error created by the shape of the clavicle. Middle third fractures account for 80% of fractures and both our AP and upshot images make the middle third appear longer in relation to lateral and medial thirds. This leads us to believe that shortening may be overestimated when measured using AP or upshot images. This leads us to advise caution when using WebPacs tools to measure shortening in clinical decision making.
