Safe Level for the Syndesmotic Stabilization: A Simulated MRI Study

CATEGORY: Trauma; Sports INTRODUCTION/PURPOSE: Great saphenous vein and saphenous nerve were reported as the high risk of injury from the syndesmotic stabilization. However, little is known about the safe level and area of the syndesmotic stabilization regarding the risks on the great saphenous neurovascular structures. This study was to demonstrate the safe level of syndesmotic stabilization via a simulated MRI study. METHODS: A total of 10 living volunteers with intact conditions of syndesmosis on their ankle MRI was recruited in this study. Each volunteer’s ankle MRI was divided into 3 groups as 15-mm, 20-mm, and 25-mm level above the ankle joint line. The simulated reduction and fixation (stabilization) line was created through the tibiofubular syndesmosis at each level in accordance with the direction guidance by Phisitkul et al. The distance between great saphenous neurovascular structures and simulated line was measured in each level of simulated stabilization for each subject. The statistical analyses using IBM SPSS version 22 were performed to demonstrate the differences among the three groups (pair 1: 15-mm vs 20 mm groups; pair 2: 20-mm vs 25-mm; pair 3: 15-mm vs 25-mm level above the ankle joint line). RESULTS: The mean distances between great saphenous neurovascular structures and simulated line of syndesmotic stabilization were shown in an attached picture. The syndesmotic stabilization at the 15-mm level above the joint line demonstrated the closest distance to the mentioned neurovascular structures. For the comparison among the three groups, pairs 2 and 3 showed the statistically significant differences at p-values as 0.004 and 0.001 respectively. A pair 1 did not show the significant difference at p- value as 0.260. CONCLUSION: Based on the results of this study, all levels of syndesmotic stabilization above the ankle joint line are safe for the great saphenous neurovascular structures. However, a 25-mm level above the joint line was the safest level for the syndesmotic stabilization when compared to other lower levels. Mini-open incision is recommended during the syndesmotic reduction and fixation on the tibial side to prevent the iatrogenic injury to the great saphenous neurovascular structures especially on the 1.5- mm and 2-mm level above the ankle joint line.