Multi-ligament injury of the knee

Findings:

Extensive knee joint effusion

Intercondylar region:

• abnormal orientation, disruption and discontinuity of the anterior cruciate ligament (ACL) fibers
• focal fluid visible between the anterior cruciate ligament and the lateral femoral condyle in the intercondylar notch

Medial compartment:

• bone contusion at the posterior medial tibial plateau
• normal meniscus
• tearing of the anterior part of the joint capsule and the deep portion of the medial collateral ligament (MCL) or medial meniscofemoral ligament
• a tear of the posterior oblique ligament (POL)

Lateral compartment:

• bone contusions at condylopatellar sulcus of the lateral femoral condyle and the posterior lateral tibial plateau
• unremarkable cartilage and lateral meniscus 
• visible Wrisberg meniscofemoral ligament with a Wrisberg pseudo-tear
• anterior and posterior, inferior popliteomeniscal fascicles not readily definable and small lesion of the lateral aspect of the superior popliteomeniscal fascicle

Patellofemoral compartment:

• high signal of the femoral attachment of the medial patellofemoral ligament (MPFL)
• unremarkable retro-patellar and trochlear cartilage
• medial patellar plica

Impression:

1. rupture / high-grade tear of the anterior cruciate ligament with bone bruises at typical locations
2. partial tear of the medial collateral ligament
3. low-grade posteromedial corner injury
4. partial medial patellofemoral ligament tear of the femoral origin
5. a suspected small tear of the popliteomeniscal fascicles
6. extensive knee joint effusion

Anterior cruciate ligament tear:

• abnormal orientation, disruption and discontinuity of the anterior cruciate ligament (ACL) fibers (red arrows)
• focal fluid visible between the anterior cruciate ligament and the lateral femoral condyle in the intercondylar notch also referred to as the empty notch sign (red arrowhead)
• bone contusions at the condylopatellar sulcus also known as deep lateral femoral notch sign (orange arrow) and at the posteromedial and posterolateral tibial Plateau (orange arrowheads) as an expression of a pivot-shift injury

Associated injuries:

• tearing of the anterior part of the joint capsule and the femoral portion of the medial meniscocapsular ligament (blue arrow)
• tearing of the posterior oblique ligament (blue arrowhead) 
• sprain of the tibial semimembranosus tendon insertion (purple arrowhead)
• a small longitudinal meniscal tear of the posterolateral border of the lateral meniscus at the insertion of the posterosuperior meniscopopliteal fascicle (purple arrow)