Avulsion fracture of the anterior cruciate ligament in a 9-year-old child.

To cite: Kose O, Ozyurek S, Guler F, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2013009426 DESCRIPTION A 9-year-old girl sustained an injury to her right knee during sliding on the playground. Immediately after the injury, she felt a sharp pain in her knee and she was unable to walk. On physical examination there was marked knee effusion without ecchymosis or deformity and the patient was keeping her knee in slight flexion. Both flexion and extension of the knee were painful. Knee ligamentous examination could not be performed due to intentional guarding. Plain radiographs demonstrated an intra-articular bone fragment in the intercondylar notch (figure 1A,B). An MRI examination revealed completely displaced avulsion fracture of the anterior cruciate ligament (ACL; figure 1C,D). Open reduction and internal fixation with two compressive screws were performed with limited arthrotomy. At the final follow-up 9 months after the injury, the fracture healed without any sign of knee instability (figure 2). Avulsion fractures of tibial spine also called as tibial eminence fracture or ACL avulsion fracture is an uncommon injury usually seen more in children than in adults. In children it is associated with forced flexion and in adults it occurs due to hyperextension injuries. 2