Fractures of the Lateral Process of the Talus: A New Classification Based on CT

Abstract Background: The common classifications of the fractures of the lateral process of the talus（LTPFs）are based on radiographs and may underestimate the complexity of LTPF, therefore, requiring a comprehensive classification based on CT(Computed tomography) scan. The aim of this study is to propose a such classification system, and to evaluate its reliability and reproducibility.Methods: On the basis of the most widely recognized classifications of Hawkins as well as McCrory-Bladin, we proposed a new and comprehensive classification based on CT scan for the LTPF. We retrospectively reviewed 42 patients involving LTPF. All fractures were classified according to Hawkins, McCrory-Bladin and new proposed classification system by three surgeons. The analysis of interobserver and intraobserver agreements was done using kappa statistics.Results: This new classification included two types based on presence of concomitant injuries or not, with type I consisting of three subtypes and type II of five subtypes. Interobserver and intraobserver reliability of the new classification system were almost perfect (κ=0.846 and 0.823, respectively)，showing a higher interobserver and intraobserver reliability compared to the Hawkins classification (κ=0.737 and 0.689, respectively) as well as McCrory-Bladin classification (κ=0.748 and 0.714, respectively). Conclusion: This new classification system for the LTPF based on CT is a comprehensive classification considering concomitant injuries. It is more reliable and reproducible and can potentially become a useful instrument for decision making of treatment options for LTPFs. Further studies on the evaluation of their clinical relevance (especially the long-term outcome) are warranted.