Identification of recurring scapular fracture patterns using 3-dimensional computerized fracture mapping.

Abstract

Scapular fracture fixation and implant selection are guided by the fracture pattern and classification, which requires accurate understanding and interpretation of the fracture lines. Three-dimensional (3D) computed tomography (CT)-based fracture pattern analysis enhances a more accurate understanding of the scapular fracture patterns. The purpose of this study was to create scapular fracture maps and identify the frequent fracture patterns using 3D reconstructed CT images. Seventy patients treated for scapular fractures, in a single hospital, were considered for this study. Their CT images were reconstructed into 3D models and the fracture fragments were virtually reduced. The reduced 3D models were first aligned on a 3D template and 2D images were captured on the anterior, posterior, and lateral views. Then each fracture image was aligned on a corresponding 2D template and the fracture lines were transferred to the template. The 3 separate views were used to accurately capture the propagation and exit of the fractures through the scapular anatomy. These fracture lines were compiled and heat maps were generated to identify the frequent fracture zones of the scapula. The observed scapular fractures propagated through multiple regions of the bone. Overall, the 3 most common exit zones in the scapula were the lateral (69%), medial (67%), and superior borders (60%). More specifically, the superior lateral border, medial base of the scapula spine, spinoglenoid notch, and mid-superior border were the most frequent zones of fracture in the scapular body. Simple intra-articular fractures (transverse or oblique type) were the most common (92%) fracture type in the glenoid region. Scapular fractures reveal repeatable patterns. The zones of recurrent fracture patterns can be identified from fracture and heat maps. Graphical plots of fracture and heat maps may assist surgical planning and implant design optimization.