The Prediction for Neutral Rotation of Tibia by the Image of Contralateral Tibia-Fibula / 대한정형외과학회잡지

ABSTRACT

Purpose: Tibial torsion is the external rotation of the distal tibia in comparison with the proximal tibia. Rotational deformity of the tibia as a complication of tibial shaft fracture means the loss of tibial torsion. Therefore, evaluating the torsion or the rotation of the distal tibia is the first step in reducing the rotational deformity of the tibia. There are two methods for evaluating the tibial torsion, a method with CT and a method with C-arm. In both methods, the anatomical landmark for evaluation is most important. The ratio of the tibiofibular overlap and fibula width (Tibiofibular Overlap Ratio) is a landmark commonly used to evaluate the tibial torsion. Materials and Methods: The tibial torsion angle and Tibiofibular Overlap Ratio of both legs in 79 cases (48 males and 31 females; mean age 46.2 years) were measured and compared. These 79 cases received 2-D CT of the knee and ankle of both legs. To evaluate the prediction for neutral rotation of the tibia using the contralateral tibia-fibula image, 20 orthopedic residents and nurses were asked to select the same rotational tibia image among the 31 rotational 3-D CT images from 15o external rotation to 15degrees internal rotation in comparison with the mirror image. Results: There was no significant between the comparisons of the tibia torsion angle and Tibiofibular Overlap Ratio in both legs in the 79 cases. Ten orthopedic residents were able to predict the tibia rotational angle within an external rotation of 3degrees and internal rotation of 3degrees. Ten nurses were able to predict the tibia rotational angle within an external rotation of 5degrees and internal rotation of 5degrees. Conclusion: The Tibiofibular Overlap Ratio may be the simple and useful method for predicting the neutral rotation of the tibia.