[The role of compression plates and screws on changes in the internal conditions in long bones]

Morphological and biomechanical changes of the course of healing of cavities after screws in compression AO plates applied for 8 weeks and simple drilling revealed that in the long-term reduction of mechanical properties of these sites as a rule a major influence is played by transverse drillingholes of 3.4 mm and holes after 4.0 mm screws rather than by plates. The healing of cavities after simple drillingholes and after removal of screws is similar. In both instances a transversally oriented trabecular bony tissue is formed, i.e. transversally oriented to the original direction of osteones. This transverse orientation of trabecular bone matrix than causes poor distribution and spread of forces acting at these sites with a different vascular supply nutrition and biochemical changes. This reduces on a long-term basis biomechanical and other properties of these sites. Tranverse drillingholes and holes after screws are more important than plates in the subsequent reconstruction of osseous tissue after their removal. Therefore it is important when treating fractures using compression plates to keep in mind this adverse late effect of transverse cavities after screws and use them as little as possible.