Distribution of posterior malleolus fracture lines in ankle fracture of supination-external rotation.

INTRODUCTION

Supination-external rotation ankle fracture is one of the most common fractures. Studies on the fracture line distribution of this fracture type are limited. The purpose of this study is to explore the distribution characteristics of intra-articular posterior malleolus fracture lines in supination-external rotation.

HYPOTHESIS

Most of the fracture lines are concentrated in a particular area.

MATERIAL AND METHODS

Computed tomography scans of a consecutive series of 70 ankle fractures of supination-external rotation were used for this study. The DICOM files were loaded into Mimics 16.0 for 3D reconstruction of the distal tibial articular surface. The intra-articular posterior malleolus fracture lines were identified after virtual fracture reduction. All the fracture lines were drawn on one picture of the distal tibial articular surface after standardization before a heat map was created based on the frequency of fracture lines.

RESULTS

Although the distribution of posterior malleolus intra-articular fracture lines varied, most of them were concentrated in an arcuate zone. The ratios of the area of posterior fracture fragment to the total area of articular surface averaged 14.96% (range, from 2.23% to 38.45%). They were most likely to enter the articular surface at 20.4% of the tangent of the posterior edge in a standardized image and exit at 58.7% of the tangent of the lateral edge.

CONCLUSIONS

In ankle fractures of supination-external rotation, most intra-articular posterior malleolus fracture lines may be distributed regularly in an arcuate zone of the articular surface.

LEVEL OF PROOF

V; Descriptive research.