Quantifying shortening of the fractured clavicle assuming clavicular symmetry is unreliable

Background One of the more commonly used methods of determining the amount of shortening of the fractured clavicle is by comparing the length of the fractured side to the length of contralateral unfractured clavicle. A pre-existing natural asymmetry can make quantification of shortening using this method unreliable. The goal of this study is to assess the side-to-side variation in clavicle length in 100 uninjured, skeletally mature adults. Materials and methods To assess the side-to-side difference in clavicle length the length of both clavicles of 100 patients on thoracic computed tomography (CT) scans were measured. Patients without a history of pre-CT clavicular injury were included. The measurements were allocated into three groups based on the amount of asymmetry ( 10 mm). Dominant side and sex were analyzed to determine influence on the length of the clavicle. Results In 30 patients (30%), an asymmetry of 5 mm or more was found. 2% of the patients had a side-to-side difference of more than 10 mm. The absolute side-to-side length difference (LD) was 3.74 mm (95% CI 3.15–4.32; p