Removal of syndesmotic screws - is sonography a precise and efficient method of guidance?

Syndesmotic injuries can lead to ankle instability. They are treated with syndesmotic screws or suture device. The necessity for screw removal remains a topic of debate. When removal is performed, it usually occurs 2 to 3 months post-operation. In such cases, the screw is typically visualized flouroscopically before removal. We describe an ultrasound-guided procedure for screw removal that avoids radiation exposure and has minimal infrastructural requirements.

In this prospective cohort study, Cohort 1 included 26 screws (18 patients) that were removed under both fluoroscopic and ultrasound guidance. This allowed for the assessment of the accuracy of ultrasound compared to fluoroscopic visualization. In Cohort 2, 22 screws (17 patients) were removed solely under ultrasound guidance to evaluate the practical applicability of the method.

A total of 35 patients were included into our study, eighteen in the first and seventeen in the second cohort respectively. In Cohort 1, the mean distance between the fluoroscopic and ultrasound measurement points of the screw heads was 2.9 mm. The mean radiation dose was 1.4 cGy/cm², and the mean operation duration was 15.2 min. Cohort 2 had a mean operative duration of 10.3 min. There were no significant differences in baseline characteristics between the groups. Radiation exposure was not present in Cohort 2. In Cohort 1, the ultrasound-guided screw localization revealed high accuracy, with the threshold < 5 mm (p = 0.040). We did not identify any significant predictors for the screw localization accuracy. The duration of the surgical procedure was similar in both groups. In the entire pooled cohort, a longer distance from skin to screw was associated with a longer surgery duration (ρ = 0.419, p = 0.012). Skin-to-screw distance was found to be the only independent predictor of surgery duration (p = 0.009).

Ultrasound-guided localisation and removal of syndesmotic screws demonstrate comparable accuracy compared to fluoroscopy, with the additional benefits of lower infrastructural requirements and associated costs. Furthermore, this method has a similar operative time to fluoroscopy and eliminates radiation exposure, supporting its feasibility as an efficient and safe alternative for syndesmotic screw removal.

In accordance with the Declaration of Helsinki the study protocol was approved by the Ethics Review Board of the University of Regensburg, Protocol number 21-2204-101.