The synthes femoral neck system (FNS): a technical tip and case series.

The femoral neck system (FNS) was recently introduced for treatment of femoral neck fractures. A novel feature is an anti-rotation screw with a diverging design from the neck bolt to provide rotational stability. Using the 4 Nm torque limiting screwdriver might cause the incomplete insertion of the screw specifically in dense or sclerotic bone. A nontorque limiting manual screwdriver should be used to complete the insertion and locking of the screw to prevent this error. We present series of seven cases with incomplete insertion of the anti-rotation screw in patient with femoral neck fractures treated with the FNS.