Adolescent athletic injuries are special in that they differ from those of the skeletally mature athlete in several respects. The physis is weaker than the ligaments, so that the typical mechanism of injury, which might be expected to result in a syndesmosis sprain of the ankle in adults with subsequent tearing of the ligaments, frequently causes an epiphyseal avulsion in children. The potential for leg length discrepancy and growth aberrations exists only if a significant amount of growth remains in the unfused epiphysis. The juvenile Tillaux fracture of the anterolateral distal tibial epiphysis is rare because it requires a specific mechanism of injury of dorsiflexion and external rotation at a time when the tibial epiphysis is fused medially but open laterally. We have also noted in these injuries a tear of the interosseous ligament, which has not previously been stressed in the literature. Intraoperative findings have helped to clarify the pathoanatomy and mechanism of injury. Anatomic reduction is necessary to prevent posttraumatic sequelae.