The haematoma and its role in bone healing

Abstract

Fracture treatment is an old endeavour intended to promote bone healing and to also enable early loading and regain of function in the injured limb. However, in today’s clinical routine the healing potential of the initial fracture haematoma is still not fully recognized. The Arbeitsgemeinschaft für Osteosynthesefragen (AO) formed in Switzerland in 1956 formulated four AO principles of fracture treatment which are still valid today. Fracture treatment strategies have continued to evolve further, as for example the relatively new concept of minimally invasive plate osteosynthesis (MIPO). This MIPO treatment strategy harbours the benefit of an undisturbed original fracture haematoma that supports the healing process. The extent of the supportive effect of this haematoma for the bone healing process has not been considered in clinical practice so far. The rising importance of osteoimmunological aspects in bone healing supports the essential role of the initial haematoma as a source for inflammatory cells that release the cytokine pattern that directs cell recruitment towards the injured tissue. In reviewing the potential benefits of the fracture haematoma, the early development of angiogenic and osteogenic potentials within the haematoma are striking. Removing the haematoma during surgery could negatively influence the fracture healing process. In an ovine open tibial fracture model the haematoma was removed 4 or 7 days after injury and the bone that formed during the first two weeks of healing was significantly reduced in comparison with an undisturbed control. These findings indicate that whenever possible the original haematoma formed upon injury should be conserved during clinical fracture treatment to benefit from the inherent healing potential.

Advances and Promises of Nutritional Influences on Natural Bone Repair

“…The reactive phase occurs immediately following trauma and is driven by the local disruption of blood vessels and surrounding soft tissue. This localized tissue injury promotes the formation of a hematoma that eventually coagulates to serve as the template for callus formation . Simultaneously, this initiates an acute inflammatory response that recruits immune cells to the fracture site .…”

Research in Fracture Healing and Its Clinical Applications in the Veterinary Practice

“…Stabilization was achieved with a unilateral external fixator with three pins distally and 3 pins proximally connected with a technovit bar [21]. The fracture area was left undisturbed, the original hematoma remained and the bone fragments and a gap between the main fractures ends were not corrected [6]. Healing was achieved in 7 weeks and proceeded through a considerable visible mineralized callus as indicated in Figure 4.…”

“…No cartilage remains; 28 days: remodeling phase. Histological samples stained with Movat Pentachrome: bone = yellow; bone marrow =purple; cartilage = blue-green, muscle = orange; connective tissue = light blue [2,4,6,15,[34][35][36][37][38][39][40][41][42][43]. Periost has been carefully elevated from the bone and was stained with hematoxylin eosin.…”

“…Therefore, most fractures heal through indirect or secondary healing [15]. Recent development in fracture treatment aims to conserve the original fracture hematoma, for example the MIPO technique fulfills this strategy [6].…”

“…The hypoxia that results from the disruption of the blood vessels during the injury is another important factor that regulates the angiogenic process in the early fracture healing. The transcription factor HIF1a (hypoxia induced transcription factor 1 alpha) that is upregulated due to the hypoxic conditions in the early bone healing phase induces the expression of VEGF (vascular endothelial growth factor) that is essential for the revascularization process [6,7]. The unfavourable conditions in the early phase of bone healing with hypoxia, low pH, high potassium and sodium concentration are difficult for specific cell subsets; however macrophages adapt and function during this phase as well as T cells, also demonstrating the tight interconnectivity of the immune reaction and the revascularisation step necessary for successful healing [8,9].…”