Length determination in midshaft clavicle fractures: validation of measurement

To evaluate different methods of length determination in acute displaced midshaft clavicle fractures.

To provide static conditions, 30 patients with healed midshaft clavicle fracture were investigated by comparing all measuring methods described in literature. The investigation included a standardized 15-degree tilted radiograph of the clavicle, a 15-degree up-tilted anteroposterior panorama radiograph of the shoulder girdle, and a posteroanterior thorax radiograph. The difference between both clavicles was also measured clinically with a tape. A computed tomography (CT) scan of the shoulder girdle was conducted with two-dimensional reconstructions of the CT scan serving as a reference method. Shortening was determined as proportional length difference. Clinical measuring was performed by 2 observers, and radiological analyses were performed by 4 independent investigators. Investigators were asked to perform repeated measurements to provide intraobserver data.

CT measurements, measurements on a posteroanterior thorax radiograph, and 15-degree up-tilted anteroposterior panorama radiograph of the shoulder girdle showed comparable repeatability. Repeatability for clinical measurements and measurements on 15-degree tilted radiographs of the clavicle were markedly lower. Agreement with CT measurements was highest for the measurements on posteroanterior thorax radiographs.

While shortening in clavicle fractures is considered an important parameter in choosing a treatment modality, a standardized method of measurement is essential. Our results suggest determining proportional length differences by taking a posteroanterior thorax radiograph.