Three-dimensional corrective osteotomies of mal-united clavicles--is the contralateral anatomy a reliable template for reconstruction?

In computer-assisted preoperative planning of corrective osteotomies, the unaffected contralateral bone often serves as three-dimensional template for the reconstruction of mal-united bones. Before applying this approach to new anatomy such as the clavicle bone, it is important to study asymmetry between the sides. The purpose of this study was to investigate bilateral symmetry of the clavicle in healthy cadavers using three-dimensional measurement techniques. Bilateral symmetry of 102 clavicles (51 cadavers, mean age: 52.19 years, 37 male) was measured based on three-dimensional models reconstructed from computed tomography. Besides length, volume, and surface, the side-differences were evaluated by considering the mirrored left clavicle as the reconstruction template and the right clavicle as the one that will be realigned by osteotomy. The relative transformation between the aligned segments was measured to express the difference with to three-dimensional translation and rotation. The same procedure was repeated using mean-sized clavicles, one for each gender, as the template. The contralateral side was a significant more accurate reconstruction template compared to a mean-sized clavicle (P < 0.001). Nevertheless, an average side-differences with respect to rotation and translation of 8.79° ± 5.2° and 3.5 mm ± 2.7 mm, respectively. The left clavicles were significant (P = 0.001) longer with 154 mm compared to the right ones (151 mm). Three-dimensional differences between the left and right clavicles exist, but can be considered as small. Therefore, the contralateral side appears to be a reliable reconstruction template, in particular compared to a mean-sized clavicle.