anterior cruciate ligament avulsion fracture

Anterior cruciate ligament (ACL) avulsion fracture or tibial eminence avulsion fracture is a type of avulsion fracture of the knee. This typically involves separation of the tibial attachment of the ACL to variable degrees. Separation at the femoral attachment is rare .

Epidemiology

It is more common in children than adults. It has been hypothesized that this may be due to the relative weakness of incompletely ossified bone relative to ligamentous fibers , or relatively increased elasticity of ligament in children .

Pathology

Mechanism

They are usually caused by forceful hyperextension of the knee or by a direct blow over distal end of femur with the knee flexed.

Meyers and McKeevers classification

A classification initially proposed by Meyers and McKeevers in 1959, later modified by Zaricznyj in 1977 , is the most common system for describing ACL avulsion fracture.

Under the Meyers and McKeever system, injuries are classified into four main types:

• type 1: minimally/nondisplaced fragment
• type 2: anterior elevation of the fragment
• type 3: complete separation of the fragment
  • type 3a: involves small portion of eminence
  • type 3b: involves the majority of the eminence
• type 4: comminuted avulsion or rotation of the fracture fragment

Radiographic features

Plain radiograph

Depending on the type, a tibial avulsion is typically seen as a fracture fragment in variable orientation involving the tibial eminence. There may be anterior translation of the femur on the tibia on the lateral view.

Siehe auch:

• Avulsionsfrakturen am Knie
• knöcherner Kreuzbandausriss
• Tibiaplateaufraktur
• proximale Tibiafrakturen
• Eminentia intercondylaris tibiae
• Meyers McKeever Klassifikation

und weiter:

• Avulsionsfraktur
• Frakturen der Eminentia intercondylaris tibiae
• vorderer Kreuzbandausriss