[Meniscal deformities associated with fractures of the tibial proximal extremity. Considerations in 7 cases]

Lateral tibial plateau fractures are a fairly frequent event in emergency clinical practice. In these fractures, when bone depression exceeds 5 mm, surgery is indicated. On the rule, conventional plain films combined with tomography can answer diagnostic questions about bone trauma. CT and MRI permit to study associated meniscocapsular injuries for better therapeutical management. Since February, 1991, we have examined 24 patients with tibial plateau fractures with conventional radiography and CT. CT was performed using thin sections, within 0 to 48 hours of the traumatic event. In our series, 7 patients had a lateral meniscal trauma associated with a fracture of the homologous tibial plateau; in all of these 7 women, surgery confirmed complete meniscal avulsion. In these cases, CT showed the following signs of meniscocapsular disinsertion: marked diastasis between capsular structure, popliteal tendon and meniscal profile; associated hypodense hemorrhagic fluid in the popliteal recess; inhomogeneous densitometry of the popliteal tendon resulting from hemorrhagic infarction. Furthermore, CT showed a characteristic and constant morphological alteration of the lateral meniscus with fibrocartilage deformation, that is with a wider or more narrow pattern relative to its normal "C"-like shape. We conclude that this morphological alteration of meniscal fibrocartilage, when associated with a tibial fracture, is a diagnostic CT sign of complete meniscal avulsion. This finding can be a useful integration to other CT signs of this meniscal injury, towards better and more complete therapeutical management.