Intraoperative comparative tests for syndesmosis: Cotton, external rotation stress, valgus, and tap-tests

Abstract

Objective: To compare the tap-test and other intraoperative tests, such as the Cotton, external rotation stress, and valgus tests, for the evaluation and diagnosis of distal tibiofibular syndesmosis injuries. This analysis is important for improving diagnostic accuracy and, consequently, optimizing the diagnosis of these injuries, which are often underdiagnosed. Methods: This retrospective cross-sectional study included 111 medical records of patients undergoing surgical treatment for ankle fractures at a referral hospital for orthopedic trauma between March 2023 and June 2024. During data collection, descriptive data were recorded, including trauma mechanism, age, sex, and Weber classification. Intraoperative data were also collected, including the syndesmosis test performed and the injury identification, which determined the need for surgical intervention, such as placement of an inter-tibiofibular screw. Results: The analysis revealed that older patients had a lower prevalence of syndesmosis injuries. The trauma mechanism did not demonstrate significant statistical relevance regarding this type of injury. The tap-test showed a higher rate of intraoperative positivity and a greater proportion of intraoperative detections than Cotton’s, external rotation, and valgus tests. However, no statistically significant difference was found between the tap test and other diagnostic tests. Conclusion: The tap-test demonstrated a high intraoperative positivity rate and detection ratio, indicating its potential as a promising test for detecting syndesmosis instability. Level of evidence IV; Retrospective study.