MR Imaging of Impingement and Entrapment Syndromes of the Foot and Ankle.

Impingement is a clinical syndrome of chronic pain and restricted range of movement caused by compression of abnormal bone or soft tissue within the ankle joint. It usually occurs following a sprain injury or repetitive microtrauma causing haemorrhage, synovial hyperplasia, and abnormal soft tissue interposition within the joint. MR imaging is particularly valuable in being able to detect not only the soft tissue and osseous abnormalities involved in these syndromes, but also a wide variety of other potential causes of ankle pain and instability that also may need to be addressed clinically.