[A correlation analysis of the ankle CT and ankle fracture classification].

OBJECTIVE: To summarize the CT features of ankle fracture and to analyze the relationship between the CT images and the most commonly used ankle fracture classification.

METHODS: With 369 cases of adult ankle fractures analyzed retrospectively, the CT images 1 cm above the ankle joint and its characteristics, the Danis-Weber classification of ankle fracture were studied, and so was the relationship between CT images and the fracture classification.

RESULTS: There were 8 forms of CT images. With a, b, and c referred to the fibular fracture, posterior malleolar fracture and interosseous tibiofibular ligament (IOL) rupture respectively. 369 CT imges had 40 cases of 0 degree injury (fibula, posterior malleolus, IOL all intact); 60 cases of Ia degree injury (fibular fracture, posterior malleolus and IOL intact), 3 cases of Ib degree injury (fibula intact, posterior malleolus fracture, IOL intact), 26 cases of Ic degree injury (fibula and posterior malleolus intact, IOL rupture); 163 cases of IIab degree injury (fibula and posterior malleolus fractures, IOL intact), 6 cases of IIac degree injury (fibular fracture, posterior malleolus intact, IOL rupture), 61 cases of IIbc degree injury (fibula intact, posterior malleollar fracture, IOL rupture); 10 cases of III degree injury (fibular fracture, posterior malleollar fracture and IOL rupture). According to the Danis-Weber classification, there were 18 cases of type A, 238 cases of type B, 94 cases of type C, and 19 cases without fibular fracture. The prevalence of IOL rupture were 0, 5.9%, and 88.3% in types A, B, and C respectively. There was a correlation between the CT image and Danis-Weber classification, the incidence of IOL rupture was changed with the severity of Danis-Weber classification, and the difference was statistically significant after the rank correlation test (Spearman R=0.781, P<0.001). IOL rupture not determined by the fracture classification was found with the CT images and the incidence was 5.9%.

CONCLUSION: Cross-sectional CT images 1 cm above the ankle joint can clearly determine the IOL injury preoperatively with a good correlation with the Danis-Weber fracture classification, IOL rupture unrecognized with the fracture classification can also be noticed with the CT image.