Imaging Case of the Week 218 Answer

The frontal x-ray of the knee shows a displaced fracture of the tibial spine (i.e. the site of the ACL attachment). The HBL view shows lipohaemarthrosis and an avulsion fracture of the posterior tibial plateau (PCL attachment).

tibial spine fracturelipohaemarthrosis HBL

This patient underwent operative repair of the tibial spine fracture.