A Comparative Inter- and Intraobserver Agreement Evaluation of Thoracolumbar Spine Injury Classification Systems and Limb Fracture Classification Schemes
Authors: Urrutia Julio , Zamora Tomas , Klaber Ianiv , Campos Mauricio , Yurac Ratko 
Published: May 2015

Introduction It has been postulated that the complex patterns of thoracolumbar spinal injuries have prevented an adequate inter- and intraobserver agreement for the most widespread classification schemes; however, limb fracture classifications have also shown variable agreements. Using trochanteric fractures of the proximal femur (TFPF) as contrast model, we evaluated if two thoracolumbar spine injuries classification systems exhibit different agreement than one limb fracture classification schemes. Patients and Methods Six evaluators (three spine surgeons and three orthopedic surgery residents) classified the radiographs and computed tomography scans of 70 patients with acute traumatic thoracolumbar injuries using the four main types of the Denis classification and the morphologic grading of the new AO Thoracolumbar Spine Injury Classification System. In addition, six evaluators (three hip specialists and the same three orthopedic surgery residents) classified the radiographs of 70 patients with TFPF using the Tronzo and the AO classification schemes. The evaluators were unaware of the patients' identification, the original classification used in their clinical care, and the treatment they received. Overall, 6 weeks later, all cases were presented in a random sequence for repeat assessment. The Kappa coefficient (κ) was used to determine inter- and intraobserver agreement. Results Interobserver agreement: For spinal injuries, using the AO classification, the mean κ was 0.62 (95% CI, 0.57–0.66) considering fracture types, and 0.55 (95% CI, 0.52–0.57) considering subtypes; using the Denis classification, κ was 0.62 (95% CI, 0.59–0.65). For TPFP, with the AO scheme, the mean κ was 0.58 (95% CI, 0.54–0.63) considering fracture types and 0.31 (95% CI, 0.28–0.33) considering subtypes; for the Tronzo classification, κ was 0.54 (95% CI, 0.50–0.57). Intraobserver agreement: For spinal injuries, using the AO classification, the mean κ was 0.77 (95% CI, 0.72–0.83) considering fracture types, and 0.71 (95% CI, 0.67–0.76) considering subtypes; for the Denis classification, κ was 0.76 (95% CI, 0.71–0.81). For TPFP, with the AO scheme, the mean κ was 0.75 (95% CI, 0.69–0.81) considering fracture types and 0.45 (95% CI, 0.39–51) considering subtypes; for the Tronzo classification, κ was 0.64 (95% CI, 0.58–0.70). Conclusion Considering the main three groups, inter- and intraobserver agreement for the AO Spine TL classification were comparable to inter- and intraobserver agreement observed for the AO classification of TPFP. What is more, if the subtypes were included, inter- and intraobserver agreement evaluating TL spine injuries were significantly better than inter- and intraobserver agreement assessing TFPF with the AO classifications. In addition, inter- and intraobserver agreement evaluations of the Denis classification of TL spine injuries were significantly better than the agreement obtained for the Tronzo classification of TFPF. Current TL spine injuries classifications allow an adequate communication among treating physicians, and they demonstrated equivalent or better inter- and intraobserver agreement than TFPF classification systems.