Review Question - QID 1367

The radiograph shows an example of a Segond fracture, most commonly caused by an anterior cruciate ligament (ACL) injury. An ACL injury would correspond best with a positive Lachman's test on physical examination. Hess et al describe the pathoanatomy of the Segond fracture which is an avulsion of the lateral tibia plateau caused by the menisco-tibial ligament. This capsular avulsion occurs during knee flexion and internal rotation of the knee, and is usually only possible after ACL injury. They found 9% of all ACL injury patients had a positive Segond sign present on plain radiographs. Stallenburg et al retrospectively reviewed radiographs of 25 patients who had sustained ACL tears and showed that posterior-lateral tibial plateau avulsion fractures were the most common radiographic finding of an ACL injury. Kezdi-Rogus et al also studied the plain-film manifestations of ACL injury and in their conclusion stressed the importance of clinical recognition of these bony avulsion injuries to raise suspicion of ACL injuries (illustration A). Furthermore, they further recommended MRI as the imaging method of choice in these patients. (Illustrations B and C show examples of an ACL tear and Segond sign on MRI respectively). Answers 2 through 5 represent a lateral meniscus tear, medial meniscus tear, PLC injury, and combined PLC and PCL injury, respectively.