[Internal fixation of acetabular both-column fractures via the ilioinguinal approach]. 
Open anatomic reduction and stable internal fixation of both-column acetabular fractures by screw and plate osteosynthesis via the ilioinguinal approach.  Displaced both-column fractures of the acetabulum with incongruence of the hip joint, central femoral head displacement, unstable hip joint, and/or loss of hip joint congruence without the potential of a secondary congruence (near anatomic fragment orientation due to ligamentotaxis).  General contraindications.  Displaced fracture of the posterior wall.  Extension of the posterior column fracture to the apex of the greater sciatic notch.  Indirect open reduction of a both-column fracture of the acetabulum that is typically characterized by a multifragmentary anterior column fracture and a simple posterior column fragment using an ilioinguinal approach.  Stepwise reduction and reconstruction of the anterior column according to the "proximal-to-distal" rule.  Reduction and fixation of the posterior column fragment against the reconstructed anterior column.  Partial weight bearing for 8-12 weeks with 15 kg body weight, beginning on the 2nd postoperative day.  Thereafter, pain-dependent weight bearing.  Thrombosis prophylaxis.  Analysis of 27 patients treated between 1991 and 2005.  A high-velocity trauma was the cause of injury in 74.1% of cases.  Most patients showed an isolated injury of the acetabulum.  In 55.5%, an additional central hip joint displacement was observed.  A primary injury to the sciatic nerve was present in 14.8% of cases.  Mean fracture gap/step was 14.3 mm.  81.5% of these fractures were anatomically reduced and stabilized; all joints were congruent.  At 2-year follow-up, 14 out of 17 patients had no signs of posttraumatic osteoarthritis.  Excellent and good functional results according to the Merle d'Aubigné Score were observed in eleven and five cases, respectively.  One patient had a moderate functional outcome.