Femoral neck fracture fixation: a biomechanical study of two cannulated screw placement techniques

This biomechanical study evaluated two different methods of femoral neck fracture fixation. Ten pairs of embalmed femora were used. A standardized midcervical osteotomy was performed. One side from each pair was fixed with either conventional (central) or calcar (cortical adjacent) screw placement. The femora pairs then were subjected to cyclic and load to failure biomechanical testing. The results demonstrated significant improved stability, load, stiffness, and displacement in all tested parameters for the group with calcar screw fixation. Grossly, the conventional fixation group tended to fail in an excessively varus position, while the calcar fixation group failed with impaction of the head on the calcar, a potentially stable position.