Imaging description

In addition to the standard anterior-posterior (AP) and lateral radiographs of the knee, medial and lateral oblique views, or tangential views, should be obtained as part of the standard radiographic assessment of the injured knee. While the lateral radiograph is sensitive for knee effusion and therefore has been suggested as a screening tool for intra-articular pathology [1], additional views are often needed to identify the fracture. Lateral and medial oblique views at 45 degrees were advocated by Daffner and Tabas to remove superimposition of the patella over the distal femur and to better show the medial and lateral tibial plateaus [2]. The combination of tangential, AP, and lateral radiographs of the knee has been reported to be more sensitive, at 85%, for acute fracture detection than AP and lateral radiographs alone (79% sensitive) [3]. Multidetector CT still plays a role in fracture characterization and preoperative planning.

Any cortical defect or unexplained sclerotic or lucent line should be viewed with suspicion, even if only seen on one projection. CT or MR should be used in confirming or excluding a fracture when radiographs are indeterminate or clinical suspicion is high despite negative radiographs.