A total of 72 patients with femoral fractures was treated between July 1997 and November 1999, 41 of them with retrograde intramedullary fixation. A minimally invasive technique was performed in 18 cases using a recently designed retrograde dilatator system (RDS) for the insertion of ACE-nail (DePuy), the reaming of the femoral canal and the locking of the distal screws. The mean age of the 18 patients (7 men and 11 women) was 49 (+/- 21) years. 8 type A, 6 type B and 4 type C fractures of the femoral shaft according to the AO classification were observed. 5 of the patients had sustained a severe polytrauma. The mean ISS of the total collective was 18 (+/- 19). No nail failed, no infection occurred, and no nerve palsies were recorded. The follow-up time was 10 (+/- 7) months. All fractures healed uneventfully. 16 patients were mobilized under full weight-bearing and regained a full range of motion without pain. In 2 cases of very old patients nursing was possible without pain. In 5 cases an implant removal was carried out in the same technique. The performed minimally invasive technique using the RDS minimizes damages to the patella ligament and the articular cartilage. It facilitates the control of rotational deformities and length discrepancies of the femur also under difficult conditions, e.g. polytrauma and obese patients.