Can monocortical miniplates provide bony compression?. An experimental model

Some maxillofacial surgeons advocate that screws in monocortical plate systems be placed eccentrically in an attempt to provide compression between bony ends. We sought to quantify the degree of displacement and compressive forces made possible by such eccentric placement in an experimental model using five miniplates and Perspex blocks to simulate mandibular fractures. The maximum displacement obtained was 0.67 mm and the maximal compressive force 5.2N (SEM=0.9, range=2.7-7.1). This demonstrates that eccentric placement of screws can achieve some compression and displacement at the fracture interface and that the forces obtained are close to those predictable from the dimensions of the burr, screw, and miniplate.