Assessment Inter- and Intraobserver Agreement in Two Radiological Indexes in True Lateral X-Rays View for Syndesmotic Reduction in Ankle Fractures

Abstract

Category: Trauma Introduction/Purpose: Malreduction of distal tibio-fibular syndesmosis in ankle fractures has been reported from 20% to 52% in surgically treated patients. Current intraoperative methods, fluoroscopy and intraoperative CT, have not improved consistently this results. Recently, new indexes to determine the normal anatomy of the syndesmosis have been published using a true lateral view of the ankle to evaluate the relation of the fibula with the tibia in the sagittal plane. These studies have been made in non- injured ankles. If these measurements could be performed intra operatively, they may improve the evaluation of syndesmotic reduction. To our knowledge this indexes have been not tested in injured ankles. The purpose of this study is to assess intra- observer and inter-observer agreement in two radiological indexes by evaluating true lateral x-ray view in surgically treated patients for ankle fractures with syndesmotic injury. Methods: Retrospective study of case series. Forty-three consecutive patients who underwent open reduction and internal fixation for ankle fractures with syndesmotic screw were evaluated. The inclusion criteria were syndesmotic injury fixed with one or two screws, and having a true lateral postoperative ankle x-ray view. Two measurements were performed: Anteroposterior Tibiofibular Ratio (APTF) and Anterior Tibiofibular Ratio (ATFR). Three independent evaluators performed the measurements. The intra-class correlation was used to determine inter- and intra-observer agreement, through statistical package SPSS 20. Results: The intra-observer and inter-observer agreement in the APTF was good to very good, with intra-class correlation values between 0.77 and 0.81; The reproducibility of the ATFR was also good to very good, but with lower intra-class correlation values between 0.62 and 0.79. Conclusion: Intra- and inter-observer concordance in APTF and ATFR in operated ankle fractures with syndesmotic injury was similar to that reported in healthy ankles. This study validates, in terms of intra and inter-observer agreement, the use of these indexes in surgically treated ankle fractures with syndesmotic repair. The next step is to compare these measurements made intra-operatively with a CT scan.