Dynamic Stabilization of Syndesmosis Injuries Reduces Complications and Reoperations Compared to Screw Fixation: a Meta-Analysis of RCTs

Abstract
Background: Several devices to obtain a dynamic fixation of the syndesmosis have been
introduced in the recent years, however their efficacy has been tested in few RCTs, without a
clear benefit over the traditional static fixation with screws.
Purpose: To perform a Level I meta-analysis of RCTs to investigate the complications,
subjective outcomes and functional results after dynamic or static fixation of acute syndesmotic
injuries.
Methods: A systematic literature search of the MEDLINE/Pubmed, Cochrane Central Register
of Controlled Trials (CENTRAL) and EBSCOhost electronic databases and clinicaltrials.gov for
unpublished studies was performed. Eligible studies were randomized controlled trials (RCTs)
comparing dynamic fixation and the static fixation of acute syndesmosis injuries. A meta
analysis was performed, while bias and quality of evidences were rated according to the
Cochrane Database questionnaire and the Grading of Recommendations Assessment,
Development and Evaluation (GRADE) guidelines.
Results: Dynamic fixation has a significantly decreased RR (0.55, p=0.003) of complications, in
particular the presence of inadequate reduction at the final follow-up (RR=0.36, p=0.0008) and
the clinical diagnosis of recurrent diastasis or instability (RR=0.10, p=0.03). The effect was more
evident compared to permanent screws (RR=0.10, p=0.0001). The reoperation rate was similar
between the two groups (RR=0.64, p=0.07); however, the overall risk was reduced after dynamic
fixation when compared to static fixation with permanent screws (RR=0.24, p=0.007). The
AOFAS score was significantly higher in patients treated with dynamic fixation of 6.06 points (p=0.005) at 3 months, 5.21 points (p=0.03) at 12 months and 8.60 points (p<0.00001) at 24
months, while the Olerund-Morlander score was similar. VAS for pain was reduced at 6 months
(-0.73 points, p=0.003) and at 12 months (-0.52 points, p=0.005) and ankle 28 ROM was increased
of 4.36° (p=0.03) with dynamic fixation. The overall quality of evidence was from “moderate” to
“very low” due to a substantial risk of bias, heterogeneity, indirectness of outcome reporting and
evaluation of a limited number of patients.
Level of Evidence: Meta-analysis of randomized controlled trials (Level I)
Key words: Syndesmosis, ankle fracture, screw, suture button, complications, dynamic fixation,
static fixation, Meta-analysis.
Conclusion:Dynamic fixation of syndesmotic injuries was able to reduce the number of complications and improve clinical outcomes as compared with static screw fixation- especially malreduction and clinical instability or diastasis - at a follow up of 2 years. A lower risk of reoperation was found with dynamic fixation as compared with static fixation with permanent screws.However, the lack of patients or personnel blinding, treatment heterogeneity, small samples and short follow up limit the overall quality of this evidence.