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

Abstract

This study aimed to develop a comprehensive classification system for fractures of the lateral process of the talus (LPTF) based on CT, and to evaluate its prognostic value, reliability and reproducibility. We retrospectively reviewed 42 patients involving LPTF with an average follow-up of 35.9 months for clinical and radiographic evaluations. In order to develop a comprehensive classification, a panel of experienced orthopedic surgeons discussed the cases. All fractures were classified according to Hawkins, McCrory-Bladin and new proposed classifications by 6 observers. The analysis of interobserver and intraobserver agreements was measured using kappa statistics. The new classification included 2 types based on presence of concomitant injuries or not, with type I consisting of 3 subtypes and type II of 5 subtypes. Average AOFAS score was 91.5 in the type Ia of new classification, 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 = 0.776 and 0.837, respectively), showing a higher interobserver and intraobserver reliability compared to the Hawkins classification (κ 0.572 and 0.649, respectively) as well as McCrory-Bladin classification (κ = 0.582 and 0.685, respectively). The new classification system is a comprehensive one that takes into account concomitant injuries and 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 LPTF.

Keywords: CT scan classification; fractures of the lateral process of the talus; interobserver agreement; reliability.