# Novel dynamic syndesmotic stabilization system improves anteroposterior and axial translation in distal tibiofibular joint

## TL;DR

A new screw-suture implant provides better joint stability than suture-button devices in treating ankle injuries, according to a biomechanical study.

## Contribution

A novel screw-suture implant is introduced for improved stabilization of length-unstable syndesmotic injuries.

## Key findings

- The screw-suture implant showed significantly smaller anteroposterior and axial/vertical movements compared to the suture-button implant.
- Stability was maintained over 5000 cycles of dynamic loading with the screw-suture implant.
- No significant differences were found in torsional or mediolateral movements between the two groups.

## Abstract

The quest for optimal treatment of acute distal tibiofibular syndesmotic disruptions is still in full progress. Using suture-button repair devices is one of the dynamic stabilization options, however, they may not be always appropriate for stabilization, for example in length-unstable syndesmotic injuries. The aim of this biomechanical study was to investigate whether a novel screw-suture implant addresses such issues compared to suture-button implants while preserving dynamic capabilities.

Eight pairs of human cadaveric lower legs were injured by complete syndesmosis and deltoid ligaments cuts, and reconstructed using a screw-suture (FIBULINK, Group 1) or a suture-button (TightRope, Group 2) implant for syndesmotic stabilization, placed 20 mm proximal to the tibia plafond. Following, all specimens were biomechanically tested over 5000 cycles under combined 1400 N axial and ± 15° torsional loading. Anteroposterior, axial/vertical, mediolateral and torsional movements at the distal tibiofibular joint level were evaluated biomechanically via optical motion tracking.

Anteroposterior and axial/vertical movements were significantly smaller and maintained over the cycles in Group 1 compared with Group 2 (p < 0.001). No further significant differences were identified between the groups (p ≥ 0.318).

Although both implant systems demonstrate ability for stabilization of unstable syndesmotic injuries, the screw-suture reconstruction provides better anteroposterior and axial/vertical stability of the distal tibiofibular joint, and maintains it over time under dynamic loading in a cadaveric study design. Therefore, it could be considered as a valid option for treatment of syndesmotic disruptions with length-unstable fibula.

Level V, Controlled Laboratory Study.