Comparison of ultrasonographic evaluation methods for ankle syndesmosis in non-weight bearing and weight bearing conditions.

Background: This study aimed to investigate ankle syndesmosis in healthy subjects under non-weight bearing (NWB) and weight bearing (WB) conditions using two US methods.

Methods: The anterior tibiofibular clear space (ATFCS) was measured in healthy subjects in NWB and WB conditions using two US procedures. Method 1 measured 10 mm above the ankle joint and Method 2 measured 30° from the line of 10 mm above the ankle joint.

Results: A total of 60 ankles from 30 subjects (male/female, 15/15) were included. There was a significant difference in the ATFCS between the two US methods (p < 0.001), and Method 2 was better at detecting the change in diastasis from NWB to WB conditions. The ATFCS was significantly greater on WB than on NWB, irrespective of the US method.

Conclusions: Method 2 was better at detecting diastasis of the syndesmosis from NWB to WB conditions. The influence of WB needs to be considered when evaluating syndesmosis using US.

Level Of Evidence: Cross-sectional cohort study; Level of evidence, Ⅳ.