Forceps reduction of the syndesmosis in rotational ankle fractures: a cadaveric study.

Background: Recent studies have shown that it is difficult to accurately reduce and assess the reduction of the syndesmosis after ankle injury. The syndesmosis is most commonly reduced with use of reduction clamps to compress across the tibia and fibula. However, intraoperative techniques to optimize forceps reductions to restore syndesmotic relationships accurately have not been systematically studied. The purpose of the present study was to evaluate the accuracy of syndesmosis reduction with different rotational vectors of clamp placement.

Methods: Ten through-the-knee cadaveric specimens were used. Markers were placed on the tibia and fibula to produce consistent clamp placement and radiographic evaluation. A computed tomographic scan of the ankle was made to serve as a control, followed by a stepwise destabilization of the anterior inferior tibiofibular ligament, syndesmosis, deltoid ligament, small posterior malleolus fracture, and large posterior malleolus fracture. Following each step in the destabilization, clamps were applied to compress the syndesmosis at varying angles and computed tomography was performed to measure the alignment of the syndesmosis as compared with that on the control scan.

Results: In all degrees of induced instability, and for all vectors of clamp placement, a small but consistent amount of overcompression of the syndesmosis was observed. The average overcompression (and standard deviation) for all samples was 0.93 ± 0.70 mm. Both obliquely oriented clamp arrangements consistently caused fibular malreductions in the sagittal plane. Placing the clamp in the neutral anatomical axis reduced the syndesmosis most accurately, with an average displacement of 0.1 ± 0.77 mm compared with control through all degrees of instability.

Conclusions: Clamp placement in the neutral anatomical axis reduced the syndesmosis most accurately in our cadaveric model, although slight overcompression was frequently observed. Placing the clamp obliquely malreduced the unstable syndesmosis.