What are signs of a high-grade anterior cruciate ligament tear or rupture?
Abnormal orientation, disruption and discontinuity of the anterior cruciate ligament fibres, fluid between the proximal anterior cruciate ligament fibres and the lateral femoral condyle and bone contusions at the condylopatellar sulcus and the posterolateral tibial plateau.
Name to specific signs in the context of an anterior cruciate ligament tear or rupture?
The empty notch sign refers to focal fluid between the anterior cruciate ligament and the lateral femoral condyle. The deep lateral femoral notch sign refers to a bone contusion or result of an impact in line with a pivot shift injury.
Give a rough outline of the structure and course of the anterior cruciate ligament.
It consists of two bundles: the anteromedial bundle and the posterolateral bundle. It takes an oblique course from the posteromedial surface of the lateral femoral condyle to the anterior intercondylar tibial eminence.
What is the deep medial collateral ligament or meniscocapsular ligament?
It is a thickening of the medial joint capsule consisting of a meniscofemoral and meniscotibial component which is adherent to the superficial part of the medial collateral ligament.
Findings:
Extensive knee joint effusion
Intercondylar region:
- abnormal orientation, disruption and discontinuity of the anterior cruciate ligament (ACL) fibres
- 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:
- rupture / high-grade tear of the anterior cruciate ligament with bone bruises at typical locations
- partial tear of the medial collateral ligament
- low-grade posteromedial corner injury
- partial medial patellofemoral ligament tear of the femoral origin
- a suspected small tear of the popliteomeniscal fascicles
- extensive knee joint effusion