The initial phase of fracture healing is specifically sensitive to mechanical conditions

Abstract

Interfragmentary movements affect the quality and quantity of callus formation. The mounting plane of monolateral external fixators may give direction to those movements. Therefore, the aim of this study was to determine the influence of the fixator mounting plane on the process of fracture healing.Identically configured fixators were mounted either niedially or anteromedially on the tibiae of sheep. Interfragmentary movements and ground reaction forces were evaluated in vivo during a nine week period. Histomorphological and biomechanical parameters described the bone healing processes.Changing only the mounting plane led to a modification of interfragmentary movements in the initial healing phase. The difference in interfragmentary movements between the groups was only significant during the first post-operative period. However, these initial diferences in mechanical conditions influenced callus tissue formation significantly. The group with the anteromedially mounted fixator. initially showing significantly more interfragmentary movements, ended up with a significantly smaller callus diameter and a significantly higher callus stiffness as a result of advanced fracture healing. This demonstrates that the initial phase of healing is sensitive to mechanical conditions and influences the course of healing. Therefore, initial mechanical stability of an osteosynthesis should be considered an important factor in clinical fracture treatment.

Cellular composition of the initial fracture hematoma compared to a muscle hematoma: A study in sheep

“…8 The fixator consisted of six Schanz screws (Ø 5 mm; Synthes, Umkirch, Germany) and two steel rods (Ø 10 mm; Synthes). This fixator was attached to the nonosteotomized tibiae in a standardized position using a drill guide.…”

Human Early Fracture Hematoma Is Characterized by Inflammation and Hypoxia

“…Removal of the FH causes prolonged fracture healing, and the implantation of FH subcutaneously led to bone formation [10,23,29,42]. Furthermore, investigations on the influence of biomechanics concerning the various phases of fracture healing indicate the inflammatory phase has a large impact on the clinical result of fracture healing: initial mechanical stability offers an optimal fracture healing, which could be brought about by an undisturbed FH [6,14,19,20,33].…”

CD73 and CD29 concurrently mediate the mechanically induced decrease of migratory capacity of mesenchymal stromal cells

“…These mechanical conditions significantly influence the long-term bone healing outcome. A certain degree of movement is benefi cial for fast and uneventful healing, whereas too little or too large movements can lead to so-called non-unions (Klein et al, 2003).…”