New Classification Based on CT and Its Value Evaluation for Fractures of the Lateral Process of the Talus

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. The aim of this study was to propose a comprehensive CT-based classification system, and to evaluate its prognostic value, reliability and reproducibility.Material and Methods: We retrospectively reviewed 42 patients involving LTPF and clinical and radiographic evaluations were performed at an average follow-up of 35.9 months. In order to create a comprehensive classification, a panel of experienced orthopedic surgeons discussed the cases. All fractures were classified according to Hawkins, McCrory-Bladin and new proposed classification system by four 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. Average AOFAS score was 91.5 in the type Ia of new classification proposed, 86 in type Ib, 90.5 in type Ic, 89 in type IIa, 76.7 in type IIb, 76.6 in type IIc, 91.3 in type IId, and 83.5 in type IIe. 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: The new classification system is a comprehensive one that takes into account concomitant injuries and it shows good prognostic value with clinical outcomes. It is more reliable and reproducible and could be a useful tool for decision-making on treatment options for LTPFs.