Effect of a Dynamic Fixation Construct on Syndesmosis Reduction: A Cadaveric Study

Abstract

Objectives: 

To explore what effect a dynamic fixation construct would have on the final reduction of the syndesmosis.

Methods: 

Syndesmotic ligaments were sectioned in 10 cadaveric specimens. The syndesmosis was intentionally malreduced with a clamp, and the distance from the anterior edge of the fibula to the anterior incisura of the tibia was measured to quantify the sagittal syndesmotic displacement (SSD). A 3.5-mm quadricortical screw was then placed, the clamp was removed, and the SSD measured. The clamp was then replaced, and a suture-button construct (Knotless Tightrope; Arthrex Inc, Naples, FL) was then placed through the bone tunnel, the clamp was again removed, and the SSD was measured.

Results: 

In all cases, the fibula reduced to within 1 mm of its native anatomical position with the dynamic construct. The static screw construct, however, maintained an identical SSD measurement as the clamped malreduction. The dynamic suture-button construct reliably improved the SSD (P < 0.0001).

Conclusions: 

Our study demonstrates that dynamic fixation constructs can help restore anatomical alignment in the case of syndesmotic malreduction. The size difference between the suture diameter and drill hole effectively allows the fibula to be pulled and seated into the tibial incisura fibularis. These findings should not be viewed as a justification to ignore the syndesmotic reduction; however, they do validate an important benefit of dynamic fixation that has been found in the recent clinical literature.

Level of Evidence: 

Therapeutic Level III.