Fixation technique influences osteogenesis of comminuted fractures

Comminuted fractures most often are associated with compromised soft tissue conditions and diminished vascularization leading to a reduced osteogenesis. In contrast to stable fixation by compression plating with lag screws, the less stable but also less invasive techniques of external fixation, unreamed nailing, or bridging plates have become increasingly popular. The aim of this study was to compare the bone healing and osteogenesis of these fixation techniques. A triple wedge osteotomy of the sheep tibia was used as a bone healing model. Internal compression plate fixation of all fragments with lag screws was used in one group. In the other three groups, only the main proximal and distal fragments were fixed by external fixation, unreamed interlocking nail, or bridging plate. The sheep with compression plate fixation and lag screws showed the worst results after 12 weeks. The periosteal and endosteal osteogenesis and the apparent density of the newly formed bone in the fracture gaps were significantly lower than those seen in the sheep in the other three technique groups. The best results were found for the bridging plate and external fixator. From these results, it can be concluded that compression plate fixation should be avoided for treatment of comminuted fractures.