Biomechanical Performance of Cannulated Compression Screws: Fixos Ø4.0, 5.0 & 7.0 mm compared to Asnis III

Introduction: The biomechanical screw performance plays a crucial role on the early interfragmentary stability and, in turn, on the fracture healing outcome. Therefore, this study compares the biomechanical performance of the cannulated headless compression screws Fixos Ø4.0, 5.0 & 7.0 mm to the standard cannulated compression screws Asnis III. Materials & Method: Interfragmentary compression force and pull-out strength were determined in a synthetic bone material. Results: The interfragmentary compression force generated by the Fixos screws was higher than the force of the ASNIS III screws (by 54%, 47% and 95%, for group Ø4.0, 5.0 & 6.5-7.0 mm, respectively). The pull-out strength associated to Fixos screws was higher than the pull-out strength of the ASNIS III screws (by 18%, 29% and 39%, for group Ø4.0, 5.0 & 6.5-7.0 mm, respectively). Discussion and conclusion: Asnis III is a proven cannulated screw system with more than ten years market experience. In terms of compression force and pull-out strength the Fixos screws demonstrated superior biomechanical performance which may allow for enhanced interfragmentary stability.