Findings: Turbo spin echo sagittal T2 weighted as well as coronal T2 weighted images of the knee demonstrate abnormal signal within the anterior cruciate ligament. In addition, there is extensive bone bruising involving the posterior aspect of the lateral tibial plateau.

Diagnosis: Tear of the anterior cruciate ligament and a nondisplaced lateral tibial plateau fracture.

Discussion: Injuries to the anterior cruciate ligament are commonly associated with other ligamentous injuries. O'Donoghue's triad consists of an anterior cruciate ligament tear, medial collateral ligament as well as medial meniscal tear.

Plain film findings of an anterior cruciate ligament tear include avulsion of the tibial eminence, a Segond fracture as well as a deepened intercondylar groove. MR imaging of an anterior cruciate ligament tear demonstrates absence, abnormal signal or course of the anterior cruciate ligament.

Reference:
Greenspan A. Orthopedic Radiology: A Practical Approach.
Lippincott, Williams & Wilkins; 2000:266-268.

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