Radiological diagnosis of pelvic ring fractures

Abstract

Traumatic fractures of the pelvic ring are relatively rare, but are associated with increased risk of mortality. Depending on injury mechanism and main vector of energy impact, a distinction is made between anteroposterior compression, lateral compression, and vertical shear (Young and Burgess classification), while the stability-related classification according to Tile distinguishes between type A (stable), type B (rotationally unstable) and type C (completely unstable). Acomprehensive modern classification is given by the AO/OTA. Plain pelvis x‑rays lack sufficient sensitivity but are still used to detect highly unstable pelvic fractures. CT has superior sensitivity and specificity. In addition to fracture classification, CT allows reliable assessment of associated vascular and bladder/urethral injuries and large soft tissue hemorrhage. MRI is unparalleled in showing bone marrow edema, cauda and plexus complications, and peripelvic soft tissue damage. MRI may also prove to be avaluable diagnostic tool for pelvic ring injuries in children, adolescents and young women, provided they are hemodynamically stable. Angiography, ultrasonography and bone scintigraphy are additional important diagnostic and therapeutic options. Knowledge of basic pelvic trauma mechanisms is important to understand the potential severity of traumatic pelvic fractures and to classify them correctly in terms of stability. Being familiar with typical concomitant injuries in pelvic ring fractures allows reliable diagnosis and their communication with the clinician. CT remains the "diagnostic workhorse". In fragile pelvic fractures, the often prolonged course with fracture progression must be taken into account, which is why MRI is of particular importance herein.