Acetabular fracture types vary with different acetabular version

Purpose: Acetabular fractures typically occur in high energy trauma. Understanding of the various contributing biomechanical factors and trauma mechanisms is still limited. While several investigations figured out what role femoral position during impact plays in distinct fracture patterns, no data exists on the influence of acetabular version on the fracture type. Our study was carried out to clarify this issue. Methods: Radiological data sets of 192 patients (145 male, 47 female, age 14-90 years) sustaining acetabular fractures were assessed retrospectively. The crossover ratio of the crossover sign and presence or absence of the posterior wall sign and ischial spine sign were used to determine acetabular retroversion on conventional radiographs. Acetabular version in the axial plane was measured on a computed tomography (CT) scan. Statistics were then performed to analyse the relationship between the acetabular fracture type according to the Letournel classification and acetabular version. Results: A significant difference (p = 0.029) in acetabular version was found between fractures of the anterior [mean equatorial edge (EE) angle 19.93 ] and posterior (mean EE angle 17.53) acetabulum in the CT scan. No difference was shown on the measurements on conventional radiographs. Conclusions: Acetabular version in the axial plane has an influence on the acetabular fracture pattern. While more anteverted acetabula were frequently associated with anterior fracture types according to the Letournel classification, retroversion of the acetabulum was associated with posterior fracture types.