A biomechanical study of a novel multi-plane elastic fixation anchor screw for the distal tibiofibular syndesmosis.

BACKGROUND

Distal tibiofibular syndesmotic injuries are common lower extremity injuries that typically require surgical intervention. TightRope technique has become a widely adopted clinical treatment for these injuries. However, the single-plane fixation nature of this technique carries risks of poor reduction and instability of the syndesmosis fixation. To address these limitations, we developed a novel multi-plane elastic fixation anchor screw, aimed at preserving the physiological micro-mobility of the tibiofibular syndesmosis while ensuring great anatomical restoration and biomechanically sound stabilization.

METHODS

This study utilized six fresh frozen ankle joint specimens to create models representing various conditions, including normal syndesmosis, injured syndesmosis, cortical screw fixation, Tightrope fixation, and novel anchor screw fixation. Each condition underwent static compression tests at different positions (plantar flexion, dorsiflexion, neutral position, varus and valgus), dynamic torsion tests (internal and external rotation), and the Cotton test. Evaluation of the reduction and stability of the syndesmosis by comparing displacement among groups and stress at the tibiotalar joint.

RESULTS

whether it is the lateral fibulotibial displacement or the axial displacement, the cortical screw group was the smallest (p < 0.05), the injury group was the largest (p < 0.05), and the other three groups showed no significant difference in most cases (p > 0.05); in the static compression test, the stress of the tibio-talar joint was the largest in the cortical screw group and the smallest in the injury group, and the other three groups still showed no significant difference in most cases (p < 0.05).

CONCLUSION

Our study demonstrates that the novel multi-plane elastic fixation anchor screw achieves better anatomical reduction and enhanced fixation stability of the distal tibiofibular syndesmosis while preserving its physiological micromobility. This fixation method may better conform to the biomechanical properties of the syndesmosis and is suitable for clinical application.