Syndesmosis Changes before and after Syndesmotic Screw Removal: A Retrospective Radiographic Study

In patients with ankle fractures complicated by syndesmotic injuries, no consensus has been reached on the best method of syndesmosis fixation using syndesmotic screws. One previous study revealed no difference in the tibiofibular overlap between two groups with or without syndesmotic screw removal. Other studies have indicated that distal tibiofibular diastasis exists after the removal of syndesmotic screws. In this study, we aimed to confirm the effect of syndesmotic screw removal on diastasis occurrence. We further analyzed the risk factors that may contribute to the widening of the tibiofibular syndesmosis.

This retrospective study involved a review of the records of 63 patients with ankle fractures accompanied by syndesmosis injuries that required syndesmotic screw fixation. Anteroposterior radiographs were analyzed for each patient at various time points, from syndesmotic screw fixation to outpatient department follow-ups after screw removal. The changes in tibia-fibula overlap (OL), tibia-fibula clear space (CS), and medial clear space (MCS) were analyzed. Further analysis was performed to reveal potential factors that may have contributed to radiographic differences.

Compared with the postoperation radiographs following syndesmotic screw fixation, OL decreased (2.0 mm) and CS increased (0.8 mm) in the anteroposterior radiographs from outpatient department follow-ups. No significant changes were noted in OL or CS after syndesmotic screw removal. However, OL decreased (1.8 mm) and CS increased (0.5 mm) before syndesmotic screw removal. No significant change in MCS occurred during the whole observation period. Linear regression analysis did not reveal any significant correlations between potentially related factors and radiographic changes.

Marked diastasis had occurred at final follow-up. Notably, the diastasis occurred before rather than after screw removal. This implies that screw removal does not significantly influence the radiographic outcomes of rotational ankle fractures.