Background: we compare the biomechanical behaviour of the proximal femoral nail (PFN) femoral neck screw with the proximal femoral nail (PFNa) helical blade, after operative treatment of trochanteric osteoporotic femoral fractures.

Methods: 208 consecutive patients who had an acute trochanteric femoral fracture (AO/ASIF A1, A2 and A3) were evaluated in a prospective randomized trial. The patients were randomized to treatment with the PFN screw (n=105) or the PFNa blade (n=103), with follow up until fracture healing. We describe the intra and postoperative complications. Implant positioning in the femoral head was also analyzed. results were assessed on plain radiographic imaging (AP and axial view) and its biomechanical implication.

Results: our review shows that PFN has a higher rate of biomechanical failure (4,8%) compared with PFNa (1.9%). Treatment success (avoiding cutout and cutin) of both devices depends on bone stock, stability of the fracture, correct reduction and implant positioning in the center-center of the femoral head.

Conclusions: PFNa’s blade demonstrates a lower incidence of cutout in the treatment of trochanteric femoral fractures. The blade improves fixation stability decreasing bone loss of the remaining bone stock, increases the contact area between implant and the femoral head and compacts the cancellous bone. We recommend PFNa for the treatment of trochanteric femoral fractures in the elderly.