Fracture healing in biological plate osteosynthesis.

In order to gain a better understanding of the healing processes after plate fixation and indirect reduction, Baumgaertel designed a reproducible fracture model for the sheep femur in 1992 so that the differences between anatomical (rigid) and biological (bridging) fixation could be investigated. It was demonstrated that indirect reduction and bridge plating was superior to direct fragment reduction and anatomical fixation in respect to radiology, biomechanics and microangiography. In this study, it was shown that bony bridging of the fracture gap and mineralization of callus occurred faster and more efficiently after indirect than after direct and anatomical reduction. Bone healing was identified as beginning in the 2.-3. week after indirect and only in the sixth week after direct reduction. The increased breaking strength of the indirectly reduced femora at 8 weeks can be attributed to this process. In addition, the consequences of applying the PC-Fix for biological plating were investigated. The values for bone healing were improved by applying a plate with only point contact to the bone, thus conserving the periosteal blood supply.