Assessment of Accuracy of Ultrasonography in Diagnosis of Non-osseous Lateral Ankle Instability in Comparison With Magnetic Resonance Imaging

Chronic ankle instability (CAI) is a condition that often develops after repeated ankle sprains, increasing the susceptibility of the ankle to move into excessive inversion when walking on unsteady surfaces. Approximately 74% of acute ankle sprains result in persistent symptoms, 30% of which progress to chronic ankle instability.[1-3] CAI is diagnosed in individuals who report pain and tenderness on the lateral aspect of the ankle, or persistent swelling and discomfort for greater than six months with a history of re-injury or clinical instability of the ankle joint.[4, 5] The primary cause of damage to the structural stability of the ankle joint is trauma by forced inversion and plantarflexion. The lateral collateral ligaments, which are more commonly affected by acute sprains, include the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), and the posterior talofibular ligament (PTFL). The ATFL is primarily responsible for preventing excessive supination and anterior translation, while also restricting plantar flexion and internal rotation.

Common diagnostic tools used to identify ankle instability include clinical testing (like Anterior Drawer Test), imaging and arthroscopy. Arthroscopic examination and magnetic resonance imaging (MRI) are considered the two most accurate methods of diagnosing injuries to lateral collateral ligaments. [7] In a retrospective study conducted by Joshy et al., in which 24 patients underwent arthroscopy and MRI of the ankle, MRI was found to have both high specificity (100%) and high sensitivity (100%) for ATFL disruption. [8-10] Ultrasound has been proven able to detect soft tissue injuries, and has even become the gold standard for the detection of injuries to the patellar and Achilles tendons. [2, 11] However, the use of ultrasound and its' ability to accurately diagnose CAI is still under debate.

When imaging the ankle, ultrasound should be able to detect synovial lesions, ligamentous injury, and distinguish soft tissue from osseous impingement.[8] Dynamic ultrasound should be also used to discover dislocation of the peroneal tendons, or intra-sheath dislocation, which is indicated by an intact retinaculum with subluxation of the peroneal tendons within the groove.[11] Aim of the work: The aim of this study is to investigate the diagnostic accuracy of ultrasonography for the assessment of non-osseous lateral ankle instability in comparison with magnetic resonance imaging (MRI).

Patients and Methods:

fifty four patients complaining of acute or chronic lateral ankle instability will be included in this study.