Retrograde locking nail osteosynthesis of distal femoral fractures with the distal femoral nail (DFN)

Non-operative treatment with immobilization or isometric traction has been abandoned as treatment for fractures of the distal femur at the end of the 1960ies. The technique of open reduction and internal fixation with a condylar plate as suggested by the AO has been the golden standard since the 1970ies. However, anatomic reconstruction of the condylar region with interfragmentary screw fixation and axial realignment of the femur shaft with a plate are challenging procedures especially in the presence of severely compromised soft tissues and put periosteal blood supply at risk. Soft tissue complications, axial malalignment and delayed fracture healing times led to the consideration of alternative techniques, such as intramedullary nailing which has been practiced with success since the 1940ies by Gerhard Küntscher and colleagues for femoral shaft fractures with minimal complication rates and improved results after closed reduction. The era of retrograde femoral nailing began with the systematic approach through the intercondylar notch by Green. This paper reviews the biomechanical properties, indication, technique as well as potential hazards and pitfalls of fracture management with the AO "distal femoral nail" (DFN). With appropriate application this technique is suitable for all fractures of the distal third of the femoral shaft including highly instable bicondylar fractures without damage to the soft tissues and the knee joint.