Modification of the measurement of the major variables in mandibular condylar fractures: angulation of sidewards displacement and shortening of the height of the ramus

Our aim was to improve the accuracy of measurement of the angulation and the shortening of the height of the ramus in fractures of the mandibular condyle using modified methods. We analysed spiral computed tomography (CT) of 67 unilateral fractures with the OsiriX v 5.0 (©Pixmeo Sarl) and Mimics 19.0 (©2016 Materialise NV, Belgium) and analysed them with SPSS (version 24.0, IBM® SPSS®). Angulation was measured using both the traditional method and our modified method. The results showed significant difference (p = 0.0001), and the values measured with the traditional method were lower, which is consistent with geometric analysis. We repositioned the condylar fragment with computer-aided surgical simulation and measured the shortened ramus. We were unable to find a significant difference between these values and those measured with our modified method (p = 0.053), so the accuracy of the modified method is acceptable. The measurement of the height of the ramus by our modified method is applicable to patients with unilateral, and those with bilateral, fractures. The accuracy in measurement of the major variables of condylar fractures is acceptable in both theory and practice. On the basis of such accurate measurement, more prospective clinical study is needed to find out the most appropriate treatment for condylar fractures.