Urrutia J, Meissner-Haecker A, Astur N, et al. - An independent inter-and intra-observer agreement evaluation of the AOSpine sacral fracture classification system was conducted. Researchers selected and categorized complete CT scans, including axial images, with coronal and sagittal reconstructions of 80 patients with sacral fractures using the morphologic grading of the AOSpine sacral classification system by six evaluators (from three different countries). Kappa coefficient (κ) was applied to establish the inter-and intra-observer agreement. It was shown that the sacral classification system permits adequate inter-observer agreement at the type level, but only moderate at the sub-types level. Further prospective studies are needed to assess if this classification system permits surgeons to decide the best treatment and to establish a prognosis in patients with sacral fractures.