Ankle fractures with Chaput fragment: A new classification system with insights into morphology and relation to...

The Chaput fragment, a bony avulsion of the anterolateral margin of the distal tibia, is a less commonly discussed fracture pattern in ankle injuries. Its significance in ankle fractures and the optimal fixation technique remains unclear due to limited literature. This study aims to describe the morphology of ankle fractures with Chaput fragment and introduce a new classification system.

We retrospectively analyzed 33 patients with ankle fractures with associated Chaput fragment treated at our institute over a 3-year period. Data on patient demographics, fracture classification, surgical approach, and fixation method were collected, and a novel classification system for Chaput fragments was proposed.

Four distinct morphological types of Chaput fragment were identified (types 1-4), and three newer variants of trimalleolar fractures were identified (anterior, lateral, and medial variants). Type 1 refers to a small avulsion fragment attached to the anterior-inferior tibiofibular ligament; Type 2 is an anterolateral oblique type; Type 3 refers to an anterolateral fragment with extension into the medial malleolus and Type 4 is a comminuted Chaput fragment. Type 1 Chaput fragment was the most prevalent (60.6%), followed by Type 2 (24.3%), Type 4 (9.1%), and Type 3 (6.1%). The fixation methods ranged from screw fixation, plate fixation, and suture fixation to combinations of these techniques or even indirect stabilization with syndesmotic screws.

Our new classification system based on morphology includes all possible variants of Chaput fracture. This preliminary data needs to be corroborated by more studies and validated by a larger number of observers.