A biomechanical study of femoral neck fracture fixation with the VHS Vari-Angle Hip Fixation System.

Femoral neck fracture fixation with a new device, the VHS Vari-Angle Hip Fixation System (Biomet Orthopaedics Inc, Warsaw, IN), was studied in 14 fresh-frozen cadaver femurs. A Pauwels class III fracture was simulated in these femurs. Seven femurs were fixed by placing the screw at a high (150 degrees) angle to the femoral axis; the other 7 femurs were fixed by placing the screw at a low (135 degrees) angle to the femoral axis. Mean compressive failure load was found to be significantly higher for the high-angle group than for the low-angle group. We concluded that compared with a low-angle screw placement (135 degrees), high-angle screw placement (150 degrees) results in a biomechanically stronger fixation.