Injury mechanism affects the stability of suture-button syndesmosis fixation

Kuan-Hao Chen,Yang-Hwei Tsuang,Hsieh-Hsing Lee,Yu-Min Huang,Chih-Hwa Chen

doi:10.1186/s13018-020-02141-3

Abstract

BackgroundAnkle syndesmosis injury is a common condition, and the injury mechanism can be sorted into pure syndesmosis injury, Weber-B, and Weber-C type fractures. This study aims to evaluate the treatment outcomes and stability of suture-button fixation for syndesmosis injury with different injury mechanisms. We hypothesized that injury mechanisms would alter the stability of suture-button fixation.MethodsWe retrospectively reviewed 63 patients with ankle syndesmosis injury who underwent surgery with TightRope (Arthrex, Naples, FL, USA) from April 2014 to February 2019. The stability of suture-button fixation with TightRope was evaluated by comparing the preoperative, postoperative, and final follow-up measurements of tibiofibular clear space (TFCS), tibiofibular overlap (TFO), and medial clear space (MCS). A subgroup analysis for each demographic group and injury type including pure syndesmosis injury, Weber-B, and Weber-C type fractures were performed.ResultsSyndesmosis was effectively reduced using TightRope. After the index surgery, the tibiofibular clear space was reduced from 7.73 to 4.04 mm, the tibiofibular overlap was increased from 3.05 to 6.44 mm, and the medial clear space was reduced from 8.12 to 3.54 mm. However, syndesmosis widening was noted at the final follow-up, especially in Weber-C type fractures (TFCS 3.82 to 4.45 mm, p < 0.01 and TFO 6.86 to 6.29 mm, p = 0.04). Though widened, the final follow-up values of tibiofibular clear space and tibiofibular overlap were in the acceptable range. Postoperatively and at the final follow-up, medial clear space was found to be significantly larger in the Weber-C group than in the pure syndesmosis and Weber-B groups (p < 0.05).ConclusionsSuture-button fixation can offer anatomic reduction and dynamic fixation in syndesmosis injuries. However, when using this modality for Weber-C type fractures, more attention should be focused on the accuracy of reduction, especially of medial clear space, and rediastasis should be carefully monitored.Trial registrationThis trial was retrospectively approved by TMU-JIRB. Registration number N202004122, and the date of approval was May 06, 2020.Level of evidenceIII

Highlights

Ankle syndesmosis injury is a common condition, and the injury mechanism can be sorted into pure syndesmosis injury, Weber-B, and Weber-C type fractures
According to the classification system of ankle fractures created by Niels Lauge-Hansen, the mechanism of such injuries can be classified as supination-adduction, supination-external rotation, pronation-abduction, and pronation-external rotation [4,5,6]
This study had 3 inclusion criteria adopted from previous studies: (1) presence of preoperative diastasis of tibiofibular clear space (TFCS) > 6 mm as measured in the standard anteroposterior (AP) view or mortise view, (2) preoperative MRI image with increased signal in T2-weighted imaging of interosseous space presenting disruption of the anteroinferior tibiofibular ligament (AITFL) or posteroinferior tibiofibular ligament (PITFL), and (3) occurrence of intraoperative movement > 3 mm after bony fixation by pulling of the fibula laterally with a towel clip [9]

Summary

Introduction

Ankle syndesmosis injury is a common condition, and the injury mechanism can be sorted into pure syndesmosis injury, Weber-B, and Weber-C type fractures. According to the classification system of ankle fractures created by Niels Lauge-Hansen, the mechanism of such injuries can be classified as supination-adduction, supination-external rotation, pronation-abduction, and pronation-external rotation [4,5,6] Another classification system based on radiographic criteria created by Danis and Weber considers the relation between the distal fibular fractures and the syndesmosis [4, 7]. According to Danis-Weber classification, a type A fracture occurs distal to the syndesmosis, which correlates with supination-adduction injury by Lauge-Hansen [7]. A Weber type B fracture occurs at the level of syndesmosis, which correlates with supination-external rotation injury by Lauge-Hansen [7]. A Weber-C type fracture occurs above the level of syndesmosis, which correlates with pronation-abduction and pronation external rotation injury by Lauge-Hansen [7]. Abundant literature on syndesmosis fixation exists, up to our knowledge there is no study about the fixation stability based on the injury mechanism

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