The discovery and clinical significance of Ilizarov's second principle of biology (the “Harbin phenomenon” of bone transport)

The understanding of Ilizarov’s biological principles is guiding clinical treatment. Ilizarov’s First Principle of Biology, Distraction Histogenesis, is a fundamental guidance for bone lengthening. The “Harbin Phenomenon” is an extension of “Transformation Histogenesis”, which was discovered by bone transport for bone defects treatment. It describes the transformation and regeneration capacities of scar tissues under slow and rhythmic distraction, and this transformation satisfies the morphological and functional requirements. This principle is a supplement to the first principle, and could be Ilizarov’s Second Principle of Biology. Together they form the basis to guide clinical bone transport treatment.