Weight-Bearing Radiographic Analysis of the Tibiofibular Syndesmosis.

Diagnosis of distal tibiofibular syndesmotic injuries includes assessment of radiographs; however, there exist no agreed on standard diagnostic criteria. Previous studies lack consistency with radiographic evaluation methods. The dynamic nature of the ankle joint supports analyzing anatomical parameters using weight-bearing films to assess for tibiofibular syndesmotic integrity. Weight-bearing tibiofibular syndesmosis radiographs of 39 male and 40 female patients were retrospectively analyzed by 3 investigators, at different levels of orthopaedic training. Measurements 1 cm above the tibial plafond for the anterior tibiofibular overlap (TFO) and tibiofibular clear space (TCS) were recorded and standardized by the fibular width (FW) at 2 time points. Data were compared to check for agreement between the sets of measurements for each rater and agreement between investigators, and to ascertain underlying gender differences. There was good intraobserver correlation (intraclass correlation coefficient [ICC] > 0.90) among investigators for each parameter. A significant difference in the TFO was noted between genders (P < .05). We establish the following radiographic (anteroposterior view) parameters for an intact syndesmosis: male patients, TCS <4.57 mm or TCS/FW <29% and TFO >9.29 mm or TFO/FW > 57%; female patients, TCS <4.28 mm or TCS/FW <30% and TFO >7.41 mm or TFO/FW >51%. Our study provides a more objective approach by utilizing weight-bearing radiographs and performing all measurements 1 cm above the tibial plafond. : Level IV.