DIAGNOSIS OF ANKLE IMPINGEMENT SYNDROME WITH MAGNETIC RESONANCE IMAGING

Abstract

Ankle pain is a common and frequently disabling clinical complaint that may be caused by a broad spectrum of osseous or soft-tissue disorders. Impingementsyndromes areconsidered oneof the most important causes of ankle pain which occurs due to friction of the joint tissues. Joint impingement is a painful syndrome caused by the friction of the joint tissues.These syndromes are classified as bone impingement, soft tissue impingement and entrapment neuropathy depending on which joint portion impinges on the others.These syndromesare anterolateral, anterior, anteromedial, posterior and posteromedial impingement and entrapment neuropathies of the ankle. Magnetic resonance imaging of the ankle disorders provides high soft-tissue contrast resolution and multiplanar capabilities in addition to quicknoninvasive tool for the diagnosis of related injuries and staging for proper management. It demonstrates soft tissue structures including muscles, tendons, ligaments, cartilages, nerves, blood vessels as well as bony structures particularly the bone marrow. Also, it permits direct visualization of spaces and compartments of the ankle, assessment of their contents including the neurovascular bundles and detection of their related abnormalities.It allows detection of tenosynovitis, tendonitis,pretendinosis, complete and partial tendon tears,sublaxation and dislocation, joint effusions, intraarticular bodies, ganglion cysts and ligamentous tearand edematous bone marrow are excellently detected by MRI. It also detects radiographically- undetected subtle bone changes and as well the changes related to the unconfidently detected bone irregularity or spurs and bone edema. Conventional MR imaging is probably most useful in posterior and posteromedial impingement, where it can identify the relative contributions of the osseous and soft tissue components. MR arthrogram seem to be the most accurate means of assessing the capsular abnormalities present in anterolateral and anteromedial impingement and for confirmation of possible concomitant injury. Compared to conventional radiographs, computed tomography and ultrasound, MRI provides the best combined sensitivity and specificity for clinical differential diagnostic consideration. Ultrasonography and MRI are complementary tools of investigation.Both US and MRI areuniquely able to demonstrate the soft tissue components of jointdisease. USwith its wide availability, lower cost and speedy examinationhas the advantage of being able toscreen multiple joints rapidly with good identification of ligament precisely as well as.MRI isconfidently done to confirm the diagnosis and extent of the lesion especially when surgical interference is planned.Hence, MRI is an efficient imaging modality in evaluating patients with chronic ankle pain.