The present invention relates to a method for fixing an intramedullary cavity nail for the treatment of unstable trochanteric fractures and to a targeting device for use in performing the steps of said method. According to the method, a recess (16) for a femur neck screw (8) for fixing the cavity nail (2) is provided in at least the lateral cortex of the femoral shaft (FS) in close distal proximity to a hole (9) for the femur neck screw such that bone fragment(s) located distally of the fracture and bone fragment(s) located proximally of the fracture relatively seen can be displaced towards each other. A targeting head (5) of the targeting device (1 ) is configured with a targeting bore (14) which is alignable with a point on the femoral shaft (FS) in close distal proximity to the hole (9) for the femur neck screw (8) for use in providing at said point, said recess (16) for the femur neck screw.