Intraobserver And Interobserver Reliability Of The New AOSpine Thoracolumbar Spine Injury Classification System

Objective: To evaluate the intraobserver and interobserver reliability and main influencing factors of the new AOSpine Thoracolumbar Spine Injury Classification System.Methods: Seventy thoracolumbar fracture patients with complete clinical data and radiologic data(including X-ray films,CT and MRI)were enrolled.Five observers were independent determined the classifications according to the New AOSpine Thoracolumbar Spine Injury Classification System.Five observers in a classification so long as there is a observer in a different type that is identified as inconsistent.After a6-week interval,the 70 cases were presented in a random sequence to the same evaluators for repeat evaluation.The Cohen Kappa coefficient(?)was used to determine the interobserver and intraobserver reliability.Result:The new AOSpine Thoracolumbar Spine Injury Classification System was found to have fair interobserver reliability and excellent intraobserver reliability.The interobserver reliabilities were Kappa=0.602 and Kappa=0.782.Respeclively in evaluation of the three types of injury,the compression fractures(Atype)and translation injuries(C type)were demonstrated fair interobserver reliability and excellent intraobserver reliability.The interobserver reliability was Kappa=0.604 and Kappa=0.662 respectively while the itraobserver reliabilities were Kappa=0.787 and Kappa=0.761 respectively.The AO System had poor reliability in evaluation of the tension band injuries(B type).The interobserver reliability was Kappa=0.362 and the intraobserver reliability was Kappa=0.657.The interobserver reliability was fair when considering the subtypes,with Kappa=0.526 and the intraobserver reliability was excellent,with Kappa=0.701,in which the poorest reliability in evaluation of the subtype of B2.The interobserver reliability was Kappa=0.214 and the intraobserver reliability was Kappa=0.633.Followed by was the subtype of A4.The interobserver reliability was Kappa=0.322 and the intraobserver reliability wasKappa=0.685.Conclusion: The new AOSpine Thoracolumbar Spine Injury Classification System was fair interobserver reliability and excellent intraobserver reliability.The poor reliability in evaluation of the subtypes A4 and B2 were the main reason for disagreement in this system.