Background: The acute lateral ankle sprain accounts for 85% of all sprains. The lateral sprain associated with other ligament injuries, such as medial and syndesmosis sprain. In the long-term approximately 20% of the acute lateral sprain develops chronic lateral ankle instability (CLAI). The definition of the chronic ankle instability is persistent pains, repeatedly ankle sprains and episodes of ankle giving away.
Study aim: The aim of this study was by using the ultrasonography to evaluate with the grade of an ankle ligament injury with the purpose to correlate the injury to patient-reported questionnaires outcome.

Methods: A cross-sectional study design performed from 15th of October to 26th of November. 26 subjects (18-40 years) from the emergency department who diagnosed with an ankle sprain (DS934) were invited to a clinical examination and performed a dynamic US examination of ankle ligaments within 15 days after the acute sprain. We evaluated with high frequency (15-6 MHz) ultrasonography the acute lateral ligament injuries (ATFL, CFL), syndesmosis injury ( AiTFL) and medial injury (dPT, TCt) only in participants with the positive clinical signs of medial injury. We follow participants up to one year with electronically (PROMQ) per. email sent every 3rd month from the date of the acute primary sprain.

Results: 16 women and 10 men and the mean age was 26.7 years wtih the mean BMI was 26.6 (17.2-41.3) participated.
Two clinical signs statistically correlated and multiple logistic regression analysis confirmed the results. Positive palpated tenderness AiTFL predicted with partial ruptured ATFL and reported pain during active plantar flexion of ankle predicted with normal CFL confirmed by the US.

Conclusion:
The study predicted patients with partial rupture of ATFL clinical present with tenderness at AiTFL point and patients presented with intact CFL reported pain during active plantar flexion. The overall clinical signs and physical examinations were unreliable factors to predicate lateral (ATFL, CFL), syndesmosis injuries (AiTFL) and medial ligament injuries compared with the US findings.