[Osteosynthesis of proximal femoral fractures with the modular interlocking system of unreamed AO femoral intramedullary nail. Initial clinical results].

The unreamed femoral nail system (UFN) features highly versatile proximal interlocking options for the treatment of a wide range of femoral fracture patterns and combinations. Besides standard interlocking modes for diaphyseal fractures, special interlocking options for subtrochanteric fractures and ipsilateral neck/shaft fractures are available. Two aiming arms can be attached to the insertion handle of the nail in a modular fashion. The standard aiming arm is designed for transverse static or dynamic locking. The special aiming arm permits spiral blade, 130 degrees, and miss-a-nail interlocking. From August 1992 to July 1994, in 10 out of 55 UFN implantations the special interlocking options were used. In 9 subtrochanteric fractures the spiral blade interlocking and in one ipsilateral neck/shaft fracture the miss-a-nail cancellous screw interlocking was applied. ASIF type A fractures with closed soft tissue damage prevailed. Fracture healing was uneventful and no implant complications or loss of reduction have been observed.