J Korean Fract Soc.  2024 Jan;37(1):39-45. 10.12671/jkfs.2024.37.1.39.

Prediction of Syndesmotic Instability according to the Lateral Malleolus Fracture Pattern in Supination-External Rotation Type Ankle Fractures: Short Oblique versus Long Oblique Fracture

• Park CJ
• Lee MS
• Lee KB

• KMID: 2551299
• DOI: http://doi.org/10.12671/jkfs.2024.37.1.39

Abstract

Purpose
This study examined whether preoperative radiological evaluations can predict syndesmotic instability according to the lateral malleolus fracture pattern in supination-external rotation-type ankle fractures.
Materials and Methods
This study enrolled 132 patients (132 ankles) with supination-external rotation stage 3 and 4 ankle fractures. Three-dimensional computed tomography was used for the morphological classification of the lateral malleolus fractures. A long oblique fracture was defined when the posterior cortical bone height of the fracture was 4.5 cm or more from the plafond of the distal tibial articular surface. A short oblique fracture was defined when the height was less than 4.5 cm. The demographic characteristics and syndesmotic instability of the two groups were evaluated.
Results
Short oblique fractures were confirmed in 102 cases, and long oblique fractures were confirmed in 30 cases. Long oblique fractures occurred at a statistically significantly higher incidence in younger ages and among males compared to short oblique fractures. Syndesmotic instability was more common in long oblique fractures.
Conclusion
In supination-external rotation-type ankle fractures, syndesmotic instability was observed in approximately 13%. Specifically, when the fracture pattern of the lateral malleolus is long oblique, the incidence of syndesmotic instability is approximately three times higher than in short oblique fractures. Therefore, meticulous evaluations of the lateral malleolus fracture pattern and establishing an appropriate treatment plan before surgery are crucial.

Keyword

Ankle; Lateral malleolus fracture; Supination-external rotation; Syndesmosis; Computed tomography