Damage to the anterior cruciate ligament may be associated with avulsion of the lateral tibial spine or the anterior intercondylar eminence. These fractures can be subtle with conventional radiography. If there is suspicion for ligamentous injury, MRI should be performed.
AP radiograph of the knee. There is a fracture at the lateral tubercle of the tibial spine. 
AP radiograph with slightly different obliquity. This shows irregularity at the region of the tibial spine. 
Lateral radiograph of the knee. This confirms the fracture at the location of the tibial spine. 
Axial CT. This image from a different patient at the level of the tibial plateau demonstrates a fracture of the tibial spine.