Internal fixation with a self-compressing plate and lag screw: improvements of the plate hole and screw design. 1. Mechanical investigation.

Abstract

For a number of years, self-compressing plates, with oval holes and using special drill guides, have been in use. Recently, the advantages offered by lag screw interfragmentary compression inserted through the plate have gained prominence. Often such screws are inserted in an inclined position toward the fracture plane for better efficiency. It has also become evident that inclined screws placed into oval holes undergo a displacement toward the fracture. Efforts to improve the effect of this technique have led to a new plate and screw interaction that is described herein. The result is versatility and efficiency of the fracture fixation.