Classification of acetabular fractures on spiral CT scans

Objective To discuss the classification of acetabular fractures on spiral CT scans.Methods Spiral CT imaging features of 131 cases of acetabular fractures were retrospectively analysed.The fracture patterns were classified according to the position of the acetabular column or wall and the extension beyond the acetabulum.Fracture and dislocation of the femoral head were excluded from this study.Results In this series,the CT manifestations could be classified into 3 types(including 9 subtypes).Type I included single-column or /and wall fracture,in which subtypeⅠ_A fracture involved in the anterior or posterior wall(n=27),subtypeⅠ_B was single anterior or posterior column fracture(n=26),subtype Ⅰ_C was single-column fractures involving the iliac ala or ischium or/and pubis(n=17),subtypeⅠ_D was single-column fractures involving the iliac ala and ischium or/and pubis(n=3).TypeⅡ fracture included both the anterior and posterior columns of the acetabulum,in which subtypeⅡA fracture was limited to the acetabulum(n=16),Ⅱ_B fracture involved in iliac wing(n=14),Ⅱ_C involved in ischium and pubic ramus(n=5),and Ⅱ_D involved in iliac wing and ischium or pubic ramus beyond the acetabulum(n=11).Type Ⅲ fracture was defined when dual-column fracture was completely separated from the axial skeleton both anteriorly and posteriorly,ie,floating acetabulum(n=12).Conclusion Spiral CT scans provides a basis for classification of acetabular fractures.This classification comprises all patterns of acetabular fractures on which to guide the diagnosis and treatment of acetabular fracture.