An Independent Interobserver Reliability and Intraobserver Reproducibility Evaluation of the New Pilon Fracture Classification System Based On CT-Scan

Category: Trauma Introduction/Purpose: Objective: To perform an independent inter-observer and intra-observer agreement assessment of the new pilon fracture classification system based on CT-scan. Summary of Background Data: Multiple classification systems have been proposed for pilon fractures, with no consensus to date of which is the most useful tool nor the one that provides the best prognostic orientation. Currently, pilon fractures are classified according to AO and Ruedi Allgower systems based on X-rays. A new pilon fracture classification system based on CT-Scan was recently described by Leonetti and Tigani in 2017. It showed substantial inter- and intra-observer agreement in the study describing it; however, an independent evaluation has not yet been performed, which is required for its wide use in clinical practice and research. Methods: CT-scans of 71 patients with acute traumatic pilon fractures were selected and classified using the morphologic grading of the new pilon fracture classification system by six evaluators (three foot and ankle surgeons and three orthopaedic surgery residents). After a six-week interval, the 71 cases were presented to the same evaluators in a random sequence for repeat evaluation. The Kappa coefficient (k) was used to determine the inter- and intra-observer agreement. Results: The inter-observer agreement was substantial when considering the fracture main types (I, II, III or IV), with k= 0.635 (0.59 - 0.67), but moderate when considering the sub-types (I, IIF, IIS, IIIF, IIIS or IV): k= 0.588 (0.56 - 0.61). The intra-observer agreement was substantial considering the fracture types, with k= 0.65 (0.62 - 0.71) and considering sub-types, k= 0.62 (0.57 - 0.66). No significant differences were observed between foot and ankle surgeons and orthopaedic residents in the overall inter- and intra-observer agreement, or in the inter- and intra-observer agreement of specific I, II, III or IV type of injuries. Conclusion: The new pilon fracture classification system based on CT-scan allows adequate agreement among different observers and by the same observer on separate occasions. Therefore, studies that use this system should be considered reliable. Future prospective studies should determine whether this classification allows surgeons to decide the best treatment for patients with tibial pilon fractures