This is Barry Belosis, one of the musculoskeletal radiology fellows at Stanford University. 25-year-old running back presented with right knee pain after hyperextending his knee, concern for knee dislocation. The patient in this case presented with this knee MRI. In here, we can see that there is complete rupture of the anterior cruciate ligament and also reported posterior cruciate ligament. Additionally, here on our coronal T2 FATSAT imaging, we can see that there is high-grade tearing of the lateral collar ligament complex at the fibular attachment with retraction of the torn fibers. Additionally, we can see this sprain of the medial collar ligament. This is in a different patient with a knee radiograph. Knee radiograph could be obtained as the initial imaging modality of choice for evaluation of patients with knee injury to exclude any bony abnormality. Here in this patient, we can see that there is large suprapatellar effusion and also, we can see this impaction deformity of the lateral femoral condyle. The patient did undergo MRI. Here in the same patient, we can see the complete rupture of the anterior cruciate ligament and the posterior cruciate ligament. A multi-ligamentous injury is defined as grossly unstable knee with disruption with at least two of the four major ligamentous structures. A two-ligament knee dislocation usually requires complete tears of both the anterior and posterior cruciate ligament. Additionally, here on our coronal T2 FATSAT imaging, we can see a bone contusion in the lateral femoral condyle and also, an MCL sprain injury as seen here. In cases of knee dislocation, we do review all the knee structures, paying special attention to specific structures that could be injured. For the meniscus, we evaluate the tear of the meniscus, if there is any flap of the meniscus, the location of the meniscus, and either medial or lateral meniscus involvement. For the ligaments, we also evaluate where the tear is, if there's any retraction. And for the bones, we do evaluate for any type of avulsion fracture, including fragment dimension, any bone contusion, or any osteochondral injuries. For any vascular injury, we want to evaluate the popliteal artery and look for perivascular hematoma or signs of thrombosis, pseudoaneurysm, or dissection. And here, for the nerves right here, we evaluate for any abnormal signal, morphology of the tibial and the common peroneal nerve. And we do describe the extent of soft tissue abnormality. For a more detailed knee MRI anatomy review, an excellent lecture by Dr. Christopher Beaulieu on YouTube is available.

2nd Edition, CASE 28

2nd Edition

Knee

musculoskeletal radiology

knee dislocation

multi-ligamentous injury

MRI assessment

Stanford