Causes / typical injury mechanism: Tibial eminence fractures, or tibial spine avulsion fractures, tend to occur in patients aged 8-14 years as a result of trauma to the knee. Common mechanisms of injury can include falling off a bike, motor vehicle accidents, and athletic participation, resulting in a twisting injury to the knee.

Classic history and presentation: The condition presents as severe knee pain and effusion due to hemarthrosis, limited range of motion (ROM), and difficulty bearing weight on the affected side. Patient history includes a trauma to the affected knee with resulting hyperextension. Patients with tibial eminence fractures may present with knee instability.

Prevalence: Tibial eminence fractures, or tibial spine avulsion fractures, are very rare in the adult population and infrequent in pediatric patients, occurring in only 3 in 100 000 children who sustain knee trauma per year.

• Age – Tibial spine avulsion fractures can occur at any age, but typically occur in patients aged 8-14 years.
• Sex / gender – No difference in occurrence has been observed.

Risk factors:

• Young age (skeletally immature)
• Athletic participation (biking, soccer, skiing, etc)

Pathophysiology: The condition occurs as a result of trauma with a rapid deceleration or hyperextension of the knee. The mechanism of injury is similar to that of an anterior cruciate ligament (ACL) tear in adults, but the incomplete ossification of the tibial eminence in pediatric patients leads to failure of the bone prior to failure of the ligaments.

Grade / classification system: The Meyers and McKeever Classification was published in 1959 and has been used to classify the degree of fracture and determine treatment methods.

• Type I fractures are nondisplaced (< 3 mm)
• Type II fractures are partially displaced with intact posterior hinge
• Type IIIA fractures are completely displaced and not rotated
• Type IIIB fractures are completely displaced and rotated
• Type IV (added by Zaricznyj in 1977) fractures are completely displaced, rotated, and comminuted