SLR - August 2020 - Shana Shetty

Sagittal Instability with Inversion is Important to Evaluate After Syndesmosis Injury and Repair: A Cadaver Robotic Study 

Reference: Patel et al. Sagittal Instability with Inversion is Important to Evaluate After Syndesmosis Injury and Repair: A Cadaver Robotic Study . Journal of Experimental Orthopaedics (2020) 7:18 https://doi.org/10.1186/s40634-020-00234-w 

Scientific Literature Review 

Reviewed By: Shana Shetty, DPM
Residency Program: Beaumont Hospital – Farmington Hills, MI

Podiatric Relevance: Syndesmotic injury is a common ankle injury with multiple options for fixation including screws versus the newer suture button techniques. The authors aim to answer the question of how much tibiofibular motion is from isolated AITFL compared to complete syndesmotic injury and outcomes associated with syndesmotic screw fixation vs. suture button repair. They believe that poor long-term outcomes result from poor tibiofibular reduction and lack of stability. The authors hypothesize that complete syndesmotic injury would lead to increased tibiofibular joint motion when compared to AITFL injury and secondly that screw fixation would restore the tibiofibular joint motion closer to the pre-injury when compared to suture button. 

Methods: The study was performed using nine fresh frozen cadaveric tibial plateau to toe specimens. The mean age was 60. They were tested using a robotic system, where 3-D tibiofibular motion was measured. Force was applied. The study measured fibular medial lateral translation, anterior-posterior translation, and external rotation. The above was measured in an intact ankle, isolated AITFL damage, AITFL, PITFL and complete injury, tricortical screws, and suture button repair.  

Results: The authors found isolated AITFL and complete injury caused an increase in fibular posterior translation in the sagittal plane. Tricortical fixation restored the ankle in all planes. This study shows that suture button repair fails to restore sagittal plane stability in response to inversion. 

Conclusions: They found that ankle injury is similar after AITFL and complete syndesmotic injury and persists after suture button fixation. This study resulted in poorer outcomes for the suture button fixation, when monitoring tibiofibular joint movement. However, the authors relate that the study results do not take into account weight bearing. In previous studies this resulted in a decreased posterior translation. As a podiatric surgeon this study re-establishes that sagittal plane instability should be considered when deciding on fixation for syndesmotic injury. 

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