Radiographic and CT evaluation of tibiofibular syndesmotic diastasis: a cadaver study

Twelve cadaver lower limbs were used for radiographic and CT assessment of the tibiofibular syndesmosis. Plastic spacers were placed in the distal tibiofibular intervals of each specimen in successive 1-mm increments until diastasis could be appreciated on the plain radiographs. All 2- and 3-mm diastases could be noted and clearly identified on CT scans, while the 1-, 2-mm, and half of the 3-mm syndesmotic diastases could not be appreciated with routine radiographs. CT scanning is more sensitive than radiography for detecting the minor degrees of syndesmotic injuries. Therefore, a CT scan can be performed in cases of syndesmotic instability after ankle injuries and for preoperative or postoperative evaluation of the integrity of the distal tibiofibular syndesmosis in cases of doubtful condition of the syndesmosis.