Morphological features of bone regeneration in simulated refracture of growing long bones

Introduction Long bone refractures can be a common injury among pediatric population. Approaches to rehabilitation of children with refractures are similar to those used for primary injuries. However, refracture healing and bone repair involve specific pathways that should be considered in rehabilitative approaches to restorative treatment. Objective To identify morphological specific features of simulated reparative processes in long bone refractures of growing animals (rats) at different stages of observation. Material and methods Two series of experiments were carried out on 36 laboratory animals (rats) to explore histological picture at the healing site of primary and repeat fractures at different stages of reparative process. Transverse fracture of the tibial shaft was simulated and fixed with external fixation device in the first series (n = 18). Tibial shaft was refractured and fixed again with external fixation device after 21 days of primary injury in the second series (n = 18). Results Delayed osteogenesis and greater period of organotypical regenerate restructuring were observed in animals with long bone refractures. Mechanism of slower osteogenesis was found to be associated with disturbed blood supply affecting cell differentiation at the refracture site. Conclusion Delayed bone repair and longer period of organotypical regenerate restructuring were specifically detected in growing animals with long bone refractures.