Causes / typical injury mechanism: Acute injury from direct crushing trauma to the fingertip, such as closing the finger in a door.

Classic history and presentation: Juxta-epiphyseal or Salter-Harris type I / II fractures of the distal phalanx with associated nail bed laceration. A pediatric patient presents after a crush injury to a fingertip with swelling, ecchymosis, and flexion deformity.

Prevalence:

• Age – Pediatric, aged 2-16 years (mean age: 8.7 years).
• Sex / gender – Male, approximately 2:1.

Pathophysiology: The fracture usually occurs at the epiphyseal / metaphyseal junction as a result of a crushing injury to the fingertip. The distal bone fragment can be pulled into flexion by the flexor digitorum profundus tendon, while the proximal portion remains extended by the terminal extensor tendon and the volar plate. Often, the nail plate becomes displaced proximally and lies superficial to the eponychial fold. The proximal portion of the lacerated nail bed, the germinal matrix, can become interposed within the fracture, resisting attempts at fracture reduction.