Approach to the essential bony parts of the pelvis which can be adapted to the fracture pattern and which causes minimal soft tissue damage. It allows exposure of the posterior and anterior columns and the roof of the acetabulum. Complex acetabular fractures such as 2-column fractures, T-fractures, displaced transverse fractures with posterior rim fragment, fractures of 1 column. Fractures which can be approached through smaller incisions, preexisting lesions of the superior gluteal artery, arterial occlusive diseases, particularly of the pelvis. Radiographs of the pelvis in anterior-posterior and two oblique news. Special radiographs and CT. Lateral decubitus with free draping of the leg. Endotracheal anaesthesia. Cell saver optional. T-shaped skin incision and gradual extension of the Kocher-Langenbeck approach depending on the fracture pattern. First extensile step: Transverse division of the fascia lata and osteotomy of the greater trochanter. Second extensile step: Osteotomy of part of the iliac crest and exposure of the outer and inner cortex of the iliac wing. Operated leg rests in a foam padded splint. Careful wound drainage, routine low dose radiation or indomethacin to prevent heterotopic ossification. CPM starting the 2nd postoperative day, mobilization starting the 2nd or 3rd day with partial weight bearing of 15 kg. Full weight bearing depends on fracture type and consolidation. Delayed wound healing with risk of infection. Injury to the superior gluteal artery with danger of necrosis of the abductor muscles. Injury through stretching of the sciatic nerve. Injury of the lateral femorocutaneous nerve. Seven patients with complex acetabular fractures were operated between June 1993 and January 1994. Use of the 1st extensile step was sufficient in 3 patients and 3 times all 4 steps were used. Postoperative necrosis of fatty tissue necessitated 2 revisions. All fractures consolidated. During the follow-up examination 1 case of heterotopic ossification was seen (Brooker grade II). Using the classification of Merle D'Aubigné we had 1 excellent, very good, 2 good and 1 satisfactory result.