Isolated posterior cruciate ligament injuries. History, mechanism of injury, physical findings, and ancillary tests.

An accurate diagnosis of an isolated PCL injury may be difficult, especially in the acute setting. A detailed history emphasizing the mechanism of injury is crucial as is a careful, complete examination of the knee. Plain and stress radiographs may be helpful in establishing the diagnosis; however, MR imaging is currently the most sensitive ancillary study available to evaluate the integrity of the posterior cruciate ligament. Failure to recognize and treat appropriately an isolated PCL disruption may result in the development of symptomatic irreversible articular surface injury.