A 9-Year-Old Boy with Pain After Twisting His Knee

Differential Diagnosis

• Meniscal tear
• ACL/PCL tear
• Maisonneuve fracture
• Displaced avulsion fracture of the tibial spine
• Dislocation

Diagnosis
The oval-shaped bone density projecting in the intercondylar notch region is a displaced avulsion fracture of the tibial spine, otherwise known as tibial eminence fractures or ACL avulsion fractures

Learnings

• ACL avulsion fractures are often associated with sports or other vigorous physical activity in children 8─13 years of age
• The fracture occurs secondary to relative weakness of incompletely ossified tibial eminence compared to native ACL fibres

Pearls for Urgent Care Management and Considerations for Transfer

• This injury is painful—the knee should be immobilized prior to transfer
• Evaluate and document neurovascular status
• Pain medication should be administered, with consideration to potential emergent surgical repair which would require NPO status
• Evaluate for more serious considerations such as an open fracture, compartment syndrome, or fracture/dislocation in the proximal or distal joint