Causes / typical injury mechanism: Flexion and internal rotation of the knee is the typical mechanism of injury in a Segond fracture / anterolateral ligament (ALL) injury.

Classic history and presentation: The typical patient is an athlete with a noncontact pivot or cutting injury, or a patient with history of blunt force applied directly to the knee.

Prevalence:

• Segond fracture is associated with anterior cruciate ligament (ACL) injury in between 75% and 100% of cases.
• Sex / gender – ACL injury has increased incidence in females.

Risk factors: Risk factors are the same as for ACL injury and include female sex, small femoral notch, and ligamentous laxity.

Pathophysiology: The Segond fracture is traditionally thought to represent a capsular avulsion fracture of the ALL off the proximal anterior lateral tibia.

Grade / classification system: No classification for the injury itself but the Lachman test on physical examination is typically reported for the associated ACL injury –

• Grade 1: < 5 mm translation
• Grade 2: 5-10 mm translation
• Grade 3: > 10 mm translation
  • A: Firm endpoint.
  • B: No firm endpoint.