The relationship between the morphology of the incisura fibularis tibiae and the pattern of posterior malleolus fractures

The science regarding the posterior malleolus (PM) of the distal tibia has grown, and indeed, the approach has evolved in recent years regarding a fracture in this region. A particular area of importance at the distal tibia is called the Incisura fibularis tibiae. Advanced imaging has aided in identifying fractures that involve the incisura. Studies have shown that the anatomy of the incisura is variable and that there are different patterns of PM fractures. This study aimed to evaluate the relationship between the anatomy of the incisura and the pattern of PM fractures. A retrospective review was done of patients who sustained PM fractures at an academic hospital over three years. The demographic characteristics, the Incisura morphology and PM fracture characteristics of preoperative bilateral ankle computed tomography (CT) scans were analysed. We analysed the incisura depth, version, width, shape, fibula shape and engagement. The relationship between the anatomy of the incisura on the unaffected ankle and the pattern of PM fracture on the injured ankle was evaluated. Incisura fibularis tibiae morphologies were measured using axial CT images from 5 mm proximal to the tibial plafond. The PM fractures were categorised according to the PM classification systems. A total of 145 cases who sustained PM fractures were included. The data revealed that females were the majority, accounting for 61%, while the right ankle was the most injured. There was a statistical difference between the types of PM fractures with regard to the incisura width (p = 0.0131). A statistically significant relationship was observed between fibula engagement and PM fractures (p = 0.049). In conclusion, certain posterior malleolus fractures were more prevalent in individuals with particular tibia incisura and fibula anatomical configurations.