Mechanical factors influencing callus healing

Interfragmentary movement and size of the fracture gap influence fracture h ealing. Limited movements promote callus formation and may result in increa sed mechanical stability. Although larger movements still promote callus fo rmation, the bony consolidation of the fracture is hampered. Fracture heali ng is also hampered if the size of the fracture gap is too large. A combina tion of large movement and large gap bears the risk of non-union. Therefore , having in mind a minimally invasive surgical approach, one should strive for good reduction of the fracture ends and flexible yet stable osteosynthe sis. Dynamization of the fracture by enabling axial movement will close the fracture gap, stimulate tissue differentiation and possibly accelerate the healing process. External mechanical stimulation, however, has not been sh own to effectively enhance the healing process under flexible fixation or i n load-bearing patients.