Diagnostic Accuracy of 2-Dimensional Computed Tomography for Articular Involvement and Fracture Pattern of Posterior Malleolar Fractures
Authors: Meijer Diederik T. , de Muinck Keizer Robert-Jan O. , Doornberg Job N. , Sierevelt Inger N. , Stufkens Sjoerd A. , Kerkhoffs Gino M. M. J. , van Dijk C. Niek ,   Ankle Platform Study Collaborative—Science of Variation Group, Engvall Andreas , Golovakha Maksym , Pereira Ernesto , Torrent Josep , Haverkamp Daniel , Bojanic Ivan , Sousa Manuel , Aragon Oscar Castro , Russo Alessandro , Cortes Carlos , Pánics Gergely , Vide João , Carvalho Manuel Santos , Thomas Zach , Tanaka Hirofumi , Dinato Mauro , Moreira António José Correia , Hatziemmanuil Dimitrios , van der Plaat Laurens Wessel , del Vecchio Javier , Zaw Htwe , Kurup Harish , Baca Emre , Zbikowski Piotr , Hemmingsson Peter , Pinheiro Miguel , Davenport James , Spennacchio Pietro , Dreiangel Niv , Bissell Iain , Toom Alar , van den Bogaert Max , Marquis Christopher , Andersen Mette , Ferrao Paulo , Darabos Nikica , Sicchiero Paolo , Keiserman Luciano , Yeap Ewe Juan , de Souza Andrè Luiz Rocha , Abdulsalam Samir , Martinelli Nicolú , Verfaillie Stefaan , da Costa Daniel , Gaspar Ana Rita , Hossain Munier , van Deurzen Derek , van den Bekerom Michel , Wiegerinck Jan-Joost , Verbeek Diederik 
Published: September 2015

Background: Up to 44% of ankle fractures have involvement of the posterior tibial margin. Fracture size and morphology are important factors to guide treatment of these fragments, but reliability of plain radiography in estimating size is low. The aim of the current study was to evaluate the accuracy of 2-dimensional computed tomography (2DCT) in the assessment of posterior malleolar fractures. Additionally, the diagnostic accuracy of 2DCT and its value in preoperative planning was evaluated. Methods: Thirty-one patients with 31 ankle fractures including a posterior malleolar fragment were selected. Preoperative CT scans were analyzed by 50 observers from 23 countries. Quantitative 3-dimensional CT (Q3DCT) reconstructions were used as a reference standard. Results: Articular involvement of the posterior fragment was overestimated on 2DCT by factors 1.6, 1.4, and 2.2 for Haraguchi types I, II, and III, respectively. Interobserver agreement on operative management (“to fix, or not to fix?”) was substantial (κ = 0.69) for Haraguchi type I fractures, fair (κ = 0.23) for type II fractures, and poor (κ = 0.09) for type III fractures. 2DCT images led to a change in treatment of the posterior malleolus in 23% of all fractures. Surgeons would operatively treat type I fractures in 63%, type II fractures in 67%, and type III fractures in 22%. Conclusion: Surgeons overestimated true articular involvement of posterior malleolar fractures on 2DCT scans. 2DCT showed some additional value in estimating the involved articular surface when compared to plain radiographs; however, this seemed not yet sufficient to accurately read the fractures. Analysis of the CT images showed a significant influence on choice of treatment in 23% with a shift toward operative treatment in 12% of cases compared to evaluating plain lateral radiographs alone. Level of Evidence: Level III, comparative study.