Anterior cruciate ligament tears and associated injuries.

Anterior cruciate ligament (ACL) tears are a commonly sustained sports injury, often occurring in association with meniscal tears and trauma to other ligamentous structures around the knee. Diagnosis can often be made clinically, but assessment may be difficult in the acute setting when there is a large joint effusion and severe pain. Plain radiographs may detect the presence of a joint effusion and any associated fractures. However, magnetic resonance imaging is vital for assessing acute knee injuries and plays an important role in deciding treatment options and planning surgical intervention. Some of the associated meniscal and ligamentous injuries can be subtle and may easily be overlooked if these structures are not scrutinized closely. This article will discuss the anatomy of the ACL and the mechanisms and initial clinical assessment of ACL injuries, and review the imaging features of ACL tears and some of the associated injuries, including the posterolateral corner structures. These associated injuries have important implications for determining treatment options and subsequent return to athletic activities.