RESUMO
Intracapsular fractures of the hip have been classified by different authors with a basis on various concepts. Pauwels classified these fractures according to the angle of inclination; Linton used trabecular disposition among the fractural fragments, and Garden described four types according to the order of displacement. The AO group used the comprehensive classification of fractures of the long bones and divided them among types, groups, and subgroups. However, the presence of posterior comminution of the femoral neck in intracapsular fractures as a factor foretelling instability was overlooked by each of the aforementioned classifications. With a basis on the factors previously described, the current authors developed a classification in which the criteria of instability in intracapsular fractures are given priority. Consequently, the characteristics of full or partial lines, angulation, displacement, and the presence of posterior comminution have been considered. Radiology is the first complementary study for diagnosis; it enables observation of the fracture line or trabecular changes in most cases and fragmental displacement and posterior comminution of the neck. In patients with stress fractures, radiographs often fail to show alterations, so a different diagnostic methodology is required. A diagnosis algorithm is presented. Differential diagnoses are focused toward diseases that may reveal images of pseudofractures.