Interfragmentary lag screws and external fixation for severe open tibial fractures: a biomechanical and clinical study.

The stability offered by the interfragmentary lag screw with a unilateral external fixator frame was studied in both experimental and prospective clinical studies. The in-vitro stability of the fixation with and without the interfragmentary lag screw was tested by a universal testing machine in compression, four-point bending, and torsion in 18 human tibiae. The in-vivo study was conducted prospectively in 18 patients with 19 severe open tibial fractures. All patients were treated with one definite surgical procedure on admission. The interfragmentary lag screw increased the sytem stiffness 47.4 times in compression, 9.9 times in bending, and 3.2 times in torsion. The immediate one-stage care of severe open fractures with a simple external fixation system in combination with the interfragmentary lag screw shortens hospitalization and may enhance healing.