[The Pitch Angle of a Locked Plate Osteosynthesis Construct]

The aim of the present study is to describe the biomechanical properties of the fracture motion of a locked plate construct.

The three dimensional fracture motion of a conventional and of a dynamic locked plate construct was observed using an optical measurement system.

Fracture motion was described in terms of delta z (mean fracture motion in direction of force application) and the pitch angle (angle between the upper and lower cylinders of osteosynthesis). It could be shown that the fracture motion of a conventional locked plate construct is only possible through the bending of the plate. The ratio of pitch angle and mean fracture motion (delta z) is a measure of the necessary degrees of bending per millimeter fracture motion. At the same pitch angle, dynamic osteosynthesis gave greater fracture motion.

With the parameters of pitch angle and mean fracture motion (delta z), it is possible to describe the whole fracture motion of locked plate fixation. Furthermore, it is possible to compare different locked plate constructs or fracture motions.