Comparison of 2 versus 3 dimensional fracture mapping strategies for 3 dimensional computerized tomography reconstructions of scapula neck and body fractures.

Fracture mapping has been used in the understanding of injury patterns in different bones. To our knowledge, there are no applications of this technique using three-dimensional (3D) morphologic fracture characteristics. Previously, scapula fractures were mapped by transferring information from 3D computed tomography to a two-dimensional (2D) template. Cole et al. determined that 3D Computerized Tomography (CT) scans were more reliable compared to plain radiographs in terms of scapular angulation, translation, and glenopolar angle measurements. Thus, we hypothesized that if there is a difference between fracture lines drawn in 3D and in 2D, then the 3D mapping would yield more accurate fracture patterns. We completed a retrospective, comparative study (evidence level III) utilizing CT imaging from a single center scapular registry. We studied ten patients with scapula fractures in whom bilateral CT scans were obtained. Fractures were mapped both two and three-dimensionally, and we measured deviations between the fracture lines that were drawn with each approach. The measured deviations ranged from 10.4 mm to 28.0 mm when comparing 2D versus 3D techniques, with the mean deviation being 4.0 mm and 10.4 mm, respectively. Half of the 2D renderings possessed hidden fracture lines that were later revealed on 3D imaging. Three-dimensional renderings were more accurate when compared to 2D fracture mapping methods. This more accurate technique will allow for better understanding of 3D morphology and provide a basis for future fracture mapping in any bone. Accurate mapping is important because surgical approach, reduction, fixation, and implant design and selection are based on fracture patterns. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:265-271, 2018.