A comparative analysis of different suture-button orientations for optimal dynamic stabilization of injured syndesmosis: A finite element study.

Abstract

Objectives: This study aims to identify the optimal suture-button orientation which supports physiological ligament healing by limiting pathological lateral and posterior translation, as well as rotational motion in the axial plane of the syndesmosis joint, through dynamic suture-button fixation.

Materials and methods: A solid ankle model and a syndesmotic injury model were developed using finite element analysis. To address the syndesmotic injury, five different suture-button fixation configurations were designed. These models were analyzed by simulating the loading conditions during the heel-off phase of the stance phase. Evaluations included fibular displacement in the anterior-posterior and medial-lateral planes, rotational angles in the axial plane, and measurements of anterior and posterior tibiofibular clear space (A-TFCS and P-TFCS).

Results: All models utilizing double suture-buttons demonstrated superior control of pathological fibular motion compared to the conventional single suture-button fixation technique (Model 1). Among them, the configuration employing double suture-buttons aligned with the anatomical orientations of the AITFL and PITFL (Model 3) was the most effective in achieving anatomical reduction and preserving physiological fibular motion. Model 5, which was specifically designed to minimize the risk of injury to neurovascular structures, tendons, and articular cartilage, reduced pathological displacement in the coronal and sagittal planes by 3% and 1%, respectively, compared to Model 3. However, it exhibited a 0.5° deficiency in limiting external rotation relative to Model 3.

Conclusion: The results obtained with Model 5 closely approximate those of the healthy ankle and demonstrate its potential as a promising fixation method which preserves critical anatomical structures. This model allows for anatomical reduction of the syndesmosis, effectively prevents pathological syndesmotic motion, and maintains physiological fibular movement. In light of these findings, we believe that Model 5 may be among the preferred techniques in the treatment strategies for syndesmotic injuries.