Fractures of the acetabulum: imaging, classification, and understanding.

For the patient with a traumatized acetabulum, accurate radiographic diagnosis and classification are the cornerstone of effective clinical care. The classification system of Judet and Letournel has led to improved management of such injuries. However, trauma-related acetabular fractures are often complex, with multiple fragments and secondary fracture lines. Furthermore, the Judet and Letournel system is complicated and easily misunderstood, reflecting the nature of the anatomy itself. Computed tomography (CT) provides information regarding the extent of the fracture and is complementary to radiography for ascertaining the spatial arrangement of fracture fragments. Three-dimensional (3D) reconstruction of CT data can be helpful in understanding the complex fracture patterns. These are divided into two main types: elementary fractures, which consist of injuries to a single structural component, and associated fractures, which are combinations of the elementary types. Three-dimensional CT is especially helpful in gaining perspective on the fracture orientation. Although questions remain as to its clinical application, 3D CT is a useful teaching tool for demonstrating the different types of acetabular fractures.