Mechanical stimulation of distraction regenerate. Mini-review of current concepts

Introduction One of the key limitations of distraction osteogenesis (DO) is the absence or delayed formation of a callus in the distraction gap, which can ultimately prolong the duration of treatment. Purpose Multiple modalities of distraction regenerate (DR) stimulation are reviewed, with a focus on modulation of the mechanical environment required for DR formation and maturation. Methods Preparing the review, the scientific platforms such as PubMed, Scopus, ResearchGate, RSCI were used for information searching. Search words or word combinations were mechanical bone union stimulation; axial dynamization, distraction regenerate. Results Recent advances in mechanobiology prove the effectiveness of axial loading and mechanical stimulation during fracture healing. Further investigation is still required to develop the proper protocols and applications for invasive and non-invasive stimulation of the DR. Understanding the role of dynamization as a mechanical stimulation method is impossible without a consensus on the use of the terms and protocols involved. Discussion We propose to define Axial Dynamization as the ability to provide axial load at the bone regeneration site with minimal translation and bending strain. Axial Dynamization works and is most likely achieved through multiple mechanisms: direct stimulation of the tissues by axial cyclic strain and elimination of translation forces at the DR site by reducing the effects of the cantilever bending of the pins. Conclusion Axial Dynamization, along with other non-invasive methods of mechanical DR stimulation, should become a default component of limb-lengthening protocols.