External torque application during assessment of syndesmotic ankle lesions: A systematic review

Syndesmotic ankle injuries, particularly those involving the distal tibiofibular joint, are challenging to diagnose due to subtle clinical presentation and complex ankle biomechanics. Both clinical and biomechanical studies struggle with accurately assessing the severity and extent of these injuries. External torque has recently shown promise in enhancing the detection and assessment of syndesmotic injuries, especially in weight-bearing computed tomography (WBCT). This study explores the impact of external torque on the assessment of syndesmotic ankle lesions in clinical versus biomechanical studies.

A systematic search was conducted using PubMed, Scopus, EMBASE, The Cochrane Library, and Web of Science. The review protocol was registered on PROSPERO (CRD42024535265). Inclusion criteria were biomechanical studies on lower limbs with intact and sectioned syndesmosis; clinical studies comparing injured ankles to healthy contralateral ones; and studies applying torque or weight-bearing to injured ankles. Exclusion criteria consisted of reviews, meta-analyses, studies on syndesmosis repair, acute injuries involving fractures, and studies lacking measurements.

Eleven studies met the inclusion criteria, including eight biomechanical and three clinical studies.

While biomechanical evidence provides a solid foundation, its translation into clinical practice requires further validation. The importance of assessment of the ankle syndesmosis under torque has been demonstrated, and the application of external torque shows promising results. Multiple studies indicate that applying an external torque between 4.5 and 7.5 [Nm] is sufficient to distinguish between intact and sectioned syndesmotic injuries. However, the need for a standardized diagnostic tool has yet to be established.