ANKLE IMPINGEMENT SYNDROMES

The ankle impingement syndrome is a frequent condition in both athlete s and the normal population. We investigated this painful syndrome fro m both a clinical and a diagnostic viewpoint. Depending on what ankle tissue impinges on the other, it is possible to distinguish bone impin gement, soft tissue impingement and peripheral nerve entrapment. For e ach of these pathologic conditions we investigated the diagnostic role of conventional radiography, Computed Tomography and Magnetic Resonan ce Imaging. The evidence of osteophytes, exostosis and presence of the os trigonum on plain films make clinical diagnosis easy in both anter ior and posterior bone impingement. CT can provide useful information about the component of the posterior ankle. MRI always adds important information about chondral or subchondral bone injuries, synovial reac tion and adjacent soft tissue involvement. The anterolateral impingeme nt syndrome is caused by repeated injuries in plantar flexion and ankl e intrarotation. MRI well detects the meniscoid injury thanks to high contrast sequences; it can also distinguish this syndrome from painful chondral and/or bony lesions at this level. MRI is also the method of choice to study sinus tarsi impingement, especially thanks to fat sup pression sequences which increase MR diagnostic capabilities in this i mportant anatomic area. Deep peroneal nerve entrapment. the medial pla ntar nerve entrapment syndrome and the tarsal tunnel syndrome are the most important entrapment neuropathies of the ankle. US and MRI are ve ry useful to study the tendon and soft tissue abnormalities causing th e anterior tarsal tunnel syndrome. CT and particularly MRI can easily detect many pathologic conditions causing the medial plantar nerve ent rapment and the tarsal tunnel syndromes. (C) 1998 Elsevier Science Ire land Ltd. All rights reserved.