Aim of the study. Aim of this study was to find out which factors influence the outcome after both column fractures of the acetabulum. Methods. We performed a retrospective analyse of 115 patients with both column acetabular fractures. The period between the injury and follow-up ranges between 2 and 19 years, 5,7 years on average. The initial displacement, the presence of a dislocation of the hip and fractures of the femoral head were analyzed on the initial radiographs. Postoperative displacement was classified according the classification of Matta. The common classifications of Helfet (posttraumatic arthrosis), Ficat/Arlet (femur head necrosis) and Brooker (periarticular calcification) were used to radiologically classify the long term results. Statistics were performed by the Chi-square-test. Results. We could find a clear tendency between the result of replacement and the radiological long-term result. 10 % of the patients with a postoperative displacement 1 mm had a