Comparison of reconstruction nails for high subtrochanteric femur fracture fixation

Subtrochanteric osteotomies were created in 18 matched pairs of embalmed cadaveric femora. The femora were stabilized with a Synthes, Zimmer, or Richards second generation femoral reconstruction nail with retrograde blade or screws. The femoral pairs were randomly assigned to groups based on nails used: Synthes versus Zimmer, Synthes versus Richards, and Zimmer versus Richards. The reconstructions were cyclically loaded in bending for 2000 cycles and then loaded to failure. The mean stiffness of the Synthes, Zimmer, and Richards reconstructions was 17%, 40%, and 40% of the intact femora, respectively. The Richards construct was the strongest, and predominately failed by fracture at the distal interlocking screw hole. The Zimmer construct failed by bending of the nail at the osteotomy site and fracture of the proximal femoral shaft. The Synthes construct was the most flexible and least strong and failed by bending of the spiral, retrograde blade with concomitant fracture of the femoral neck. This study indicates that fixation of subtrochanteric femur fractures with a Synthes spiral blade or Richards or Zimmer reconstruction nails provides stable fixation for postoperative loading conditions. However, the Richards and Zimmer nails were able to withstand higher loads than was the Synthes nail before failure.